Incremental Growth of the European Oyster, Ostrea edulis: Seasonality information from Danish kitchenmiddens 9781841714370, 9781407324463

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BAR S1057 2002 MILNER

Incremental Growth of the European Oyster Ostrea edulis

INCREMENTAL GROWTH OF THE EUROPEAN OYSTER

Seasonality information from Danish kitchenmiddens

Nicky Milner

BAR International Series 1057 B A R

2002

Published in 2016 by BAR Publishing, Oxford BAR International Series 1057 Incremental Growth of the European Oyster, Ostrea edulis © N Milner and the Publisher 2002 The author's moral rights under the 1988 UK Copyright, Designs and Patents Act are hereby expressly asserted. All rights reserved. No part of this work may be copied, reproduced, stored, sold, distributed, scanned, saved in any form of digital format or transmitted in any form digitally, without the written permission of the Publisher.

ISBN 9781841714370 paperback ISBN 9781407324463 e-format DOI https://doi.org/10.30861/9781841714370 A catalogue record for this book is available from the British Library BAR Publishing is the trading name of British Archaeological Reports (Oxford) Ltd. British Archaeological Reports was first incorporated in 1974 to publish the BAR Series, International and British. In 1992 Hadrian Books Ltd became part of the BAR group. This volume was originally published by Archaeopress in conjunction with British Archaeological Reports (Oxford) Ltd / Hadrian Books Ltd, the Series principal publisher, in 2002. This present volume is published by BAR Publishing, 2016.

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in loving memory of my father, William Peter Milner

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Acknowledgments This volume represents work carried out for my doctoral thesis, the aim of which was to develop a method for analysing the seasonality of the European oyster, Ostrea edulis. Thanks are due to a great many people who provided information, help and support whilst I was conducting the research and also to some who have been a great help and encouragement over the period of time I have taken to convert the thesis into this volume. Geoff Bailey supervised me during my first year of Ph.D. in Cambridge and although this could not continue on his appointment as Professor of Archaeology in Newcastle he continued to offer advice throughout the three years. I am also very grateful to him for subsequently re-reading many of the re-written chapters in this volume. I am indebted to Søren H. Andersen for my visits to Denmark when he has taken me to visit many of the Ertebølle sites, supplied oysters for this project and for all his subsequent help and guidance. He too has read over the chapters on the archaeological application of the technique. I would also like to thank William Fletcher for reading through much of this work, and for all his helpful advice, patience and encouragement. This research would not have been undertaken without the initial encouragement of Tina Dudley and I am therefore very grateful to her for that and for her support throughout, especially for advice and help in thin sectioning techniques. I also received much encouragement from my Ph.D. supervisor, Charly French and my advisor Paul Mellars. I am very grateful to the Natural Environment Research Council for the funding over the three years. Corpus Christi College, Cambridge was also very supportive and I would particularly like to thank Margaret Cathie. Thanks also go to the Department of Archaeology, University of Cambridge and the McDonald Institute for their assistance in my research. The Grahame Clark laboratory was a stimulating environment to work in and I am especially grateful to Jessica Rippengal, Preston Miracle and Marsha Levine. The work on modern control samples would not have been possible without the help of Peter Walker and Ron Lee of MAFF, and the supply of oysters from Peter Hawtin of Southampton Public Health Authority, Bill Devonish from Chelmsford Public Health Authority and Deborah Brookes, Angela Aires and Timothy Robbins from Truro Public Health Authority. Thanks go to Martin Convery, Seasalter Shellfish Ltd., Whitstable who showed me around their shellfish beds and gave me some oysters of known age. I am grateful to Lizzy and Adrian Nash for accommodating me on that visit and attempting, in vain, to get me to eat an oyster. I would also like to thank the Cambridge departmental administrator Jane Woods, the Faculty secretary Val Shadrack and departmental secretaries Vicki Culverwell, and Chrissy Spriggs who received and stored three boxes of week-old, odorous oysters every month for a year and a half. Information on modern sea and air temperatures, and salinities was kindly provided by Captain John Clayton, harbour master at Whitstable, Michael Carr of Falmouth Port Authority, Malcolm Sach, Environmental Health for Maldon District Council, and Alec Harmer, Environmental Health Services, New Forest District Council. Thanks also go to Lillian Kjaer of the Danish Meterological Office who provided environmental information for Denmark and to the educational services and press offices at the British Meteorological Office for information on average temperatures in the UK. I have been given much advice from experts, in the fields of oysters and of Danish archaeology, and special thanks go to Jessica Winder, Chris Richardson, Peter Rowley-Conwy and Kristian Pedersen. In terms of technical help, Graham Lawson showed me how to make acetate peels, I had help with the S.E.M. from Patrick Echlin and Terry Burgess, and technical support from Ian Chaplin from Buehler Ltd. with the thin sectioning equipment. Many thanks go to Laura Pugsley for administering the blind tests and taking part as the novice tester. I am very grateful to Neil Brodie who has always been willing to discuss various problems and has particularly helped me with computer matters. Thanks also go to Brian Boyd, Jenny Doole, Kevin Greene, Henry Kenny, Gwil Owen, Dave Redhouse, Penny Spikins, John Stewart, Mark White, Todd Whitelaw and Nick Winder for advice and support. I would also like to acknowledge Karen Milek, Chantal Conneller, John Stewart, William Davies and especially Lila v

Janik and Paul Lane for their discussions following a talk on this research to the Palaeolithic Mesolithic Discussion Group in Cambridge, 1998. I have been fortunate to receive so much encouragement during my work and would particularly like to thank Martin Johnson, Dominic Powlesland and Tim Schadla-Hall and to remember Mr. W. Gatenby. Special thanks also to my sister Carol, Elaine Posnett and Charles and Patty Posnett. I am also extremely grateful to my mother, Jenny Milner, not only for hours of proof reading of various drafts but also for her continuing guidance at the difficult moments. Any errors in this volume are of course my own.

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Contents Chapter 1: Seasonality Studies ...........................................................................................................................1 Seasonality Studies: Methods and Interpretations............................................................................................................2 The Ertebølle Culture .....................................................................................................................................................3 The Transition to Agriculture .........................................................................................................................................5 An Evaluation of EBK Seasonality Studies .....................................................................................................................6 Outline of the Volume ....................................................................................................................................................8

Chapter 2: The Oyster ...........................................................................................................................................9 Incremental Growth Analysis........................................................................................................................................10 Biology and Physiology of Ostrea edulis .......................................................................................................................10 Reproduction...................................................................................................................................................11 The animal......................................................................................................................................................11 Filtering and feeding .......................................................................................................................................12 Shell structure .................................................................................................................................................12 External stress factors......................................................................................................................................13 Monitoring the Life Cycle.............................................................................................................................................14

Chapter 3: Modern Control Sample ...............................................................................................................15 Problems of Interpretation.............................................................................................................................................16 Ecological analogy ..........................................................................................................................................16 Individual variation .........................................................................................................................................17 Sampling issues...............................................................................................................................................18 The Modern Control Sample.........................................................................................................................................18 The sample......................................................................................................................................................18 Southampton ...................................................................................................................................................22 Chelmsford .....................................................................................................................................................24 Truro...............................................................................................................................................................25 Whitstable.......................................................................................................................................................26 Summary of Differences................................................................................................................................................27 Sub-Sampling ...............................................................................................................................................................27 Summary......................................................................................................................................................................28 Chapter 4: Methodology .....................................................................................................................................29 Methodologies ..............................................................................................................................................................30 Differential staining ........................................................................................................................................30 Oxygen isotope analysis ..................................................................................................................................30 Scanning electron microscopy .........................................................................................................................30 Acetate peels ...................................................................................................................................................30 Thin sectioning ...............................................................................................................................................31 Experiments with Methodologies ..................................................................................................................................31 Method for Thin Sectioning Ostrea edulis ....................................................................................................................32 Preparing the oysters .......................................................................................................................................32 Sectioning the valves.......................................................................................................................................32 Impregnation...................................................................................................................................................33 Preparing the sections .....................................................................................................................................33 Bonding to a slide ...........................................................................................................................................34 The thin section...............................................................................................................................................34 Summary......................................................................................................................................................................34 vii

Chapter 5: Interpretation of the Modern Control ......................................................................................35 Annual Lines and Disturbance Lines ............................................................................................................................36 The “classic” annual line.................................................................................................................................36 Disturbance lines.............................................................................................................................................40 Difference between locations and sites.............................................................................................................40 Time of Formation of Annual Lines..............................................................................................................................44 Seasonality ...................................................................................................................................................................45 Measurements .................................................................................................................................................45 Measuring growth of Ostrea edulis..................................................................................................................46 Structural observations ....................................................................................................................................49 Summary......................................................................................................................................................................49 Chapter 6: Blind Testing ....................................................................................................................................61 Blind Test 1..................................................................................................................................................................62 Slide selection .................................................................................................................................................62 Runs 1,2 and 3 ................................................................................................................................................62 Observations ...................................................................................................................................................62 Results..........................................................................................................................................................................64 Seasonality......................................................................................................................................................64 Age .................................................................................................................................................................65 Location ..........................................................................................................................................................66 Blind Test 2..................................................................................................................................................................66 Seasonality......................................................................................................................................................67 Age .................................................................................................................................................................67 Summary......................................................................................................................................................................67 Chapter 7: Archaeological Sites and Sampling............................................................................................69 Norsminde....................................................................................................................................................................70 Visborg.........................................................................................................................................................................72 Dyngby.........................................................................................................................................................................74 Havnø, Eskelund and Lystrup .......................................................................................................................................75 Cataloguing and Sub-Sampling.....................................................................................................................................75 Cataloguing.....................................................................................................................................................75 Sub-sampling for thin sectioning.....................................................................................................................75 Norsminde ......................................................................................................................................................76 Visborg ...........................................................................................................................................................77 Dyngby ...........................................................................................................................................................77 Havnø, Eskelund and Lystrup..........................................................................................................................77 Summary of Sampling ..................................................................................................................................................77 Chapter 8: Archaeological Interpretation .....................................................................................................79 Thin Sectioning ............................................................................................................................................................80 Interpretation................................................................................................................................................................88 The ambient environment................................................................................................................................88 Seasonality......................................................................................................................................................90 Age .................................................................................................................................................................93 Summary......................................................................................................................................................................93

Chapter 9: Discussion ..........................................................................................................................................95 Methodology.................................................................................................................................................................96 Sampling ......................................................................................................................................................................96 Seasonality Results .......................................................................................................................................................97 Conclusion....................................................................................................................................................................98

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Appendix 1...............................................................................................................................................................99 Chelmsford data ...........................................................................................................................................................99 Southampton data .......................................................................................................................................................103 Truro data...................................................................................................................................................................111 Whitstable data ...........................................................................................................................................................114

Appendix 2.............................................................................................................................................................116 List of slides chosen by administrator..........................................................................................................................116 Blind test 1, Run 1......................................................................................................................................................117 Blind test 1, Run 2......................................................................................................................................................118 Blind test 1, Run 3......................................................................................................................................................119 Blind test 2: novice .....................................................................................................................................................120

Appendix 3.............................................................................................................................................................122 Norsminde..................................................................................................................................................................122 Visborg.......................................................................................................................................................................126 Dyngby.......................................................................................................................................................................128 Eskelund.....................................................................................................................................................................129 Lystrup .......................................................................................................................................................................129 Havnø.........................................................................................................................................................................130

Bibliography .........................................................................................................................................................131 Index ........................................................................................................................................................................137

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Figures Chapter 1: Seasonality Studies Figure 1.1 Resource availability schedule for the Danish Ertebølle............................................................................ 5 Figure 1.2 Seasons of exploitation for the resources at Bjørnsholm ........................................................................... 6 Figure 1.3 Revised seasons of exploitation for the resources at Bjørnsholm ............................................................... 7

Chapter 2: The Oyster Figure 2.1 Ostrea edulis lying in the left valve........................................................................................................ 12 Figure 2.2 Section through an oyster shell............................................................................................................... 12

Chapter 3: Modern Control Sample Figure 3.1: Section through cockle.......................................................................................................................... 16 Figure 3.2: Calendar and growth events mentioned in text ...................................................................................... 17 Figure 3.3: Maps to show locations of modern control samples ............................................................................... 19 Figure 3.4: Measurements taken from each valve.................................................................................................... 21 Figure 3.5: Graph showing average measurements of hinge length to shell length .................................................. 21 Figure 3.6: Graph to show average measurements for Southampton ........................................................................ 22 Figure 3.7: Graph to show average measurements for 2 Southampton groups.......................................................... 23 Figure 3.8: Graph to show temperature readings for 2 Southampton sites................................................................ 23 Figure 3.9: Graph to show salinity readings for 2 Southampton sites....................................................................... 24 Figure 3.10: Graph to show average measurements for Chelmsford ........................................................................ 24 Figure 3.11: Graph to show variations in air and sea temperatures for Chelmsford ................................................. 25 Figure 3.12: Graph to show variations in salinity for Chelmsford............................................................................ 25 Figure 3.13: Graph to show average measurements for Truro.................................................................................. 26 Figure 3.14: Graph to show temperature readings for Truro sites ............................................................................ 26 Figure 3.15: Graph to show salinity readings for Truro sites ................................................................................... 26

Chapter 4: Methodology Figure 4.1: Sectioning an oyster.............................................................................................................................. 32

Chapter 5: Interpretation of the Modern Control Figure 5.1: Thin section of shell from Whitstable collected in April........................................................................ 37 Figure 5.2: Thin section of shell from Chelmsford collected in May........................................................................ 38 Figure 5.3: Thin section of shell from Truro collected in April................................................................................ 39 Figure 5.4: Thin section of shell from Southampton showing very disturbed growth ............................................... 41 Figure 5.5: Thin section of shell from Chelmsford showing disturbance lines ......................................................... 42 Figure 5.6: Thin section of shell from Southampton collected in May ..................................................................... 43 Figure 5.7: Illustration of a thin section from Whitstable ........................................................................................ 46 Figure 5.8: Graph to show measurements taken for a sample of Truro shells........................................................... 47 Figure 5.9: Graph to show relative growth index..................................................................................................... 48 Figure 5.10: Thin section of shell from Southampton, collected in June .................................................................. 50 Figure 5.11: Thin section of shell from Southampton, collected in July................................................................... 21 Figure 5.12: Thin section of shell from Southampton, collected in August .............................................................. 52 x

Figure 5.13: Thin section of shell from Southampton, collected in September ......................................................... 53 Figure 5.14: Thin section of shell from Chelmsford, collected in October................................................................ 54 Figure 5.15: Thin section of shell from Chelmsford, collected in November............................................................ 55 Figure 5.16: Thin section of shell from Southampton, collected in December.......................................................... 56 Figure 5.17: Thin section of shell from Chelmsford, collected in January................................................................ 57 Figure 5.18: Thin section of shell from Southampton, collected in February............................................................ 58 Figure 5.19: Thin section of shell from Southampton, collected in March ............................................................... 59

Chapter 7: Archaeological Sites and Sampling Figure 7.1: Map of northern Jutland showing the location of the six sites................................................................ 70 Figure 7.2: Plan of the Norsminde excavations ....................................................................................................... 71 Figure 7.3: Plan of the midden at Visborg............................................................................................................... 73 Figure 7.4: The 1997 excavations at Visborg .......................................................................................................... 73 Figure 7.5: Visborg section 1 .................................................................................................................................. 74 Figure 7.6: Visborg section 2 .................................................................................................................................. 74 Figure 7.7: Dyngby section 1 .................................................................................................................................. 74 Figure 7.8: Dyngby section 2 .................................................................................................................................. 75 Figure 7.9: Graph to show hinge length against shell length for each site ............................................................... 76

Chapter 8: Archaeological Interpretation Figure 8.1: Thin section of eroded shell from Lystrup ............................................................................................. 80 Figure 8.2: Thin section of oyster from Dyngby ...................................................................................................... 81 Figure 8.3: Thin section of oyster from Eskelund .................................................................................................... 82 Figure 8.4: Thin section of oyster from Eskelund .................................................................................................... 83 Figure 8.5: Thin section of oyster from Visborg ...................................................................................................... 84 Figure 8.6: Thin section of oyster from Havnø ........................................................................................................ 85 Figure 8.7: Thin section of oyster from Neolithic levels of Norsminde .................................................................... 86 Figure 8.8: Thin section of oyster from Mesolithic levels of Norsminde .................................................................. 87 Figure 8.9: Graph showing average monthly temperatures in Britain ...................................................................... 89 Figure 8.10: Graph showing average monthly temperatures in Denmark................................................................. 89 Figure 8.11: Histogram showing seasonality of gathering at Mesolithic Norsminde ................................................ 90 Figure 8.12: Histogram showing seasonality of gathering at Neolithic Norsminde................................................... 90 Figure 8.13: Histogram showing seasonality of gathering at Visborg....................................................................... 91 Figure 8.14: Histogram showing seasonality of gathering at Dyngby....................................................................... 91 Figure 8.15: Histogram showing seasonality of gathering at Eskelund .................................................................... 91 Figure 8.16: Histogram showing seasonality of gathering at Havnø......................................................................... 91 Figure 8.17: Histogram showing seasonality of gathering at Lystrup ....................................................................... 91 Figure 8.18: Graph of estimated age against size..................................................................................................... 92 Figure 8.19: Graph of estimated age against size for Norsminde shells ................................................................... 92 Figure 8.20: Graph of estimated age against size for Visborg shells ........................................................................ 94 Figure 8.21: Graph of estimated age against size for Dyngby shells......................................................................... 94

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Tables Chapter 3: Modern Control Sample Table 3.1: Number of oysters received each month................................................................................................. 19 Table 3.2: Dates and batch numbers for each site at Chelmsford ............................................................................. 20 Table 3.3: Dates and batch numbers for Truro ........................................................................................................ 20 Table 3.4: Date and batch numbers for Southampton .............................................................................................. 20 Table 3.5: Number of shells sub-sampled for Southampton ..................................................................................... 28 Table 3.6: Number of shells sub-sampled for Truro................................................................................................. 28 Table 3.7: Number of shells sub-sampled for Chelmsford........................................................................................ 28

Chapter 5: Interpretation of the Modern Control Table 5.1: Tallies of annual lines present for Whitstable ......................................................................................... 44 Table 5.2: Tallies of annual lines present for Truro................................................................................................. 44 Table 5.3: Tallies of annual lines present for Chelmsford........................................................................................ 44 Table 5.4: Tallies of annual lines present for Southampton ..................................................................................... 45 Table 5.5: Measurements between annual lines and the relative growth index, Truro.............................................. 48

Chapter 6: Blind Testing Table 6.1: Results from run 1, seasonality............................................................................................................... 63 Table 6.2: Statistics for each run and the total ........................................................................................................ 64 Table 6.3: Age estimates for each of the 3 runs ....................................................................................................... 65 Table 6.4: Locations and sites identified ................................................................................................................. 66 Table 6.5: Assessments of months made by novice.................................................................................................. 68 Table 6.6: Results of age estimates made by novice ................................................................................................. 68

Chapter 7: Archaeological Sites and Sampling Table 7.1: Seasonality readings of otoliths from Norsminde .................................................................................... 71 Table 7.2: Norsminde - shells catalogued and total number of interpretable sections ............................................... 76 Table 7.3: Visborg - shells catalogued and total number of interpretable sections.................................................... 77 Table 7.4: Dyngby - shells catalogued and total number of interpretable sections .................................................... 77 Table 7.5: Havnø, Eskelund, Lystrup - total number of interpretable sections.......................................................... 77

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CHAPTER 1

Seasonality Studies

In recent decades, assessing the seasonality of faunal remains, where possible, has become standard practice in archaeological research, particularly in the study of the Mesolithic period. Traditionally, the study of faunal remains from Mesolithic sites has taken an economic line of questioning, analysing aspects such as resource availability, subsistence strategies, calorific intake and butchery practices. More recently, however, increasing emphasis on the social complexity of hunter-gatherer groups such as the Late Mesolithic Ertebølle of Denmark has shifted the focus of research away from a purely economic approach. Seasonality studies not only provide information concerning subsistence strategies but may also be linked to numerous other facets of a society. Indeed Monks (1981) using ethnographic examples has demonstrated that dispersion and aggregation of populations, settlement patterns, prestige, kin group ownership and belief systems may all be tied intimately to seasonality and the availability of resources. Therefore, in investigating the seasonality of resource procurement we are not simply studying when a group hunted, gathered or fished a particular species and when it did not: rather, we are approaching an understanding of seasonal activities which were inextricably tied into all parts of a people’s way of life. Therefore, as recognition of the important role of seasonality studies in archaeology grows, so too must critical evaluation of the methods, techniques and interpretation of seasonality. This volume represents the work carried out for my doctoral thesis, the aim of which was to develop a method for analysing the seasonality of the European Oyster, Ostrea edulis. Patterning, in the form of growth breaks or bands in the shell micro-structure, has been shown to occur in other molluscs and has sometimes been used to ascertain the season of gathering for archaeological samples, but until now this has never been attempted on Ostrea edulis. The objective was to apply the method to oysters from Danish shell middens (køkkenmøddinger) in order to obtain information on the season of gathering at these sites. This is a particularly interesting area of Mesolithic studies as it is believed that the Ertebølle culture was a socially complex society of hunter gatherers, living off abundant coastal resources which enabled them to lead a sedentary existence. What is also of major importance is that through objects found, such as pottery and axes, it can be demonstrated that the Ertebølle people had contact with the farmers in the south, and yet agriculture was not adopted for 1000 years (Price 2000). Why such a long time lag exists has fired many debates and oysters have played a significant role in some of these (Rowley-Conwy 1984). A summary of the Ertebølle culture and the transition to agriculture in Denmark will be outlined in this chapter in order to show how evidence of seasonal procurement of resources is incorporated into interpretations, and to emphasise the necessity for a fresh line of evidence.

CHAPTER 1 sites of Meiendorf and Stellmoor in the Ahrensburg tunnel valley, North Germany (Krause 1937). At both sites large quantities of reindeer were found and it is thought that these sites were seasonally occupied and had been located at certain points in the valley expressly for the exploitation of the reindeer during their late summer/autumn migrations. This has been likened to migration patterns of Lapp, Inuit and Siberian people of the present day (Grønnow 1987; Rust 1937; 1943; Bratlund 1993). Similarly the Ertebølle site of Aggersund, Denmark, is thought to have been a seasonal special purpose camp for hunting whooper swans, the number of these bones found being unique among other small contemporary sites. Assuming that the swan migrates in a similar manner to the present day, the site is interpreted as being occupied in the late autumn/winter when these birds would have been available (Møhl 1979).

Seasonality Studies: Methods and Interpretations Monks (1981) has summarised approaches to procuring seasonal information from faunal remains but further steps have since been made. Many new techniques have been developed and applied to a large number of different species in order to obtain information as to what season or time of year certain animals were hunted, fished or gathered. Methods include empirical techniques where the physical structures of the faunal remains are examined, as well as approaches that assess the probable seasonal availability of resources using ethnographic and/or ecological analogues. In recent years, attention has often been focused on the investigation of seasonality by analysing the incremental growth structures of various living organisms. These are usually found in teeth or shells where increments of material such as enamel, cementum or calcite are added to previous growth over time. Changes in the rate of growth may be affected by the environmental conditions and nutrition, which may result in seasonal patterning in the structure. The phenomenon is well known in trees, where a ring is formed with each year. Patterning may also occur in teeth, shell or fish bone. The structure however, may also show other bands/lines which may be the result of either periodic or non-periodic breaks in growth due to events such as spawning, rutting, tidal cycles or fluctuations in the ambient environment.

Star Carr is a prime example of a site where many different lines of evidence have been used to interpret seasonality but will be used here to emphasise problems that have arisen with the analyses. This well-known Mesolithic site in the Vale of Pickering, North Yorkshire was first excavated by Grahame Clark between 1949 and 1953 (Clark 1954). The large quantities of red deer antler and bone were seen to indicate that red deer was the most important resource at the site. The majority of antlers found at Star Carr had been broken from the skulls, therefore these deer must have been carrying their antlers when killed, indicating procurement between October and March before antler shedding takes place in April. The shed antlers were originally thought to represent April collection because red deer have been known to eat their antlers in order to replenish calcium and as none of them had been gnawed they must had been gathered before this could have taken place (Fraser and King 1954). Clark (1972) later proposed a model of migration whereby the red deer would have herded from the North Yorkshire Moors down to the Vale to seek shelter in the winter. It was suggested that the Mesolithic population of Star Carr would have followed them, red deer appearing to be their main source of subsistence.

There are, however, many alternative methods that may be used to investigate seasonality. Mellars and Wilkinson (1980) measured the size of otoliths of saithe from Oronsay. In the first few years of a fish’s life, the length of the otolith is proportional to age and by using modern control samples it was possible to relate the patterns in size to seasons. Likewise, oxygen isotope analysis has been used instead of incremental analysis when investigating the seasonality of shellfish (e.g. Kennet and Voorhies 1996). In these types of studies variations in the isotopes 16O and 18O are measured and compared to provide information on water temperature, which may be related to seasonal fluctuations. The readings for the edge of the shell can then be translated into the season at which it ceased to grow; i.e. it was gathered and died. The work on cockles by Deith combines both incremental analysis and oxygen isotope methods (Bailey et al. 1983; Deith 1985; 1986; 1988; 1989). Other approaches include the study of physiological events such as tooth eruption and wear which, with the use of modern control samples, may be related to seasons. These types of studies have been carried out on animals such as pig (Rowley-Conwy 1981), roe deer (Legge and Rowley-Conwy 1988) and gazelle (Davis 1987).

Using red deer antler as a seasonal indicator of occupation at this site has since proven to be unreliable. Large amounts of red deer antler had been worked into harpoons and blanks and it was therefore a valuable raw material that may have been collected there or elsewhere and stored to be worked at any point in the year (Pitts 1979). It has also been shown that red deer only eat their antlers when they are in need of nutrition, which is unlikely to have been the case in the Vale of Pickering, in which case the shed antlers may have been collected at any time (Pitts 1979). Moreover Clark’s model of seasonal transhumance has been rejected as it was based on studies of modern red deer in Scotland (Darling 1937) and Norway (Ingebrigsten 1924), both of which are very different environments to that at Star Carr. Red deer can tolerate a wide range of habitats and it has been suggested that in a forested area, as at Star Carr, the red deer would not have migrated (Legge and Rowley-Conwy 1988).

A very common, cheaper and less time consuming method of interpreting seasonal exploitation entails identifying the presence and absence of remains and the probable seasonal availability of resources using ethnographic and/or ecological analogues. Some animals are migratory and their presence in the archaeological record may indicate that they could only have been exploited at certain times of the year. One of the earliest attempts at this was made for the Upper Palaeolithic

Other evidence for winter occupation has been implied from two scapula, one elk and one red deer, which both had lesions in a state of healing. This was evidence that these animals had been hunted and hit at least twice. Noe-Nygaard (1975) 2

SEASONALITY STUDIES •

inferred from this that it was more likely they had been killed in wintertime as during the summer game spreads over larger areas and the chances of shooting the same animals is much smaller. This hypothesis is only based on the evidence from two animals and once again red deer in a forested environment do not tend to herd (Legge and Rowley-Conwy 1988).

•

The roe deer antlers, which were attached to the skulls, appear to indicate summer exploitation as this species shed in early autumn. In this case it is feasible to use roe deer antler as an indicator of when the animals were being hunted because the antler was not worked and it is unlikely it was collected for any other purpose (Jacobi 1978). It has also been noted that the crane and the white stork were migrant species visiting in the summer (Grigson 1981), although a minimum number of only 1 of each species was found and it is of course possible that they were natural deaths on the edge of the lake.

•

•

The number of conflicting views led Legge and RowleyConwy (1988) to re-assess the faunal collection using a dental development method of wear and eruption on the roe deer jaws. Comparing the evidence with modern reference material it was suggested that the kill period covered late spring and summer. It was also noted that neonatal roe deer, red deer and elk indicated early summer occupation and no specimens pointed definitely to winter visits except a single elk mandible which indicated late summer or autumn hunting. More recently, however, seasonality of deer has once more been reassessed using radiographs of mandibular tooth development in red deer, the results suggesting a winter human presence at the site (Carter 1998).

For all these reasons it is more informative to use as many lines of evidence as possible when interpreting seasonality of habitation and exploitation of animals. Recently there have been some critical reviews of techniques used (e.g. Claassen 1993; Deith 1985; Gordon 1993) but these will be covered in more detail in the relevant chapters (3, 4 and 5) on control samples, methodology and interpretation.

The Ertebølle Culture The sites sampled for this study are all from Jutland and therefore, for the purposes of this volume, this section will concentrate on the archaeology of Jutland, although in some areas it is necessary to consider southern Sweden and the islands of Denmark where Ertebølle sites are also found. The vast majority of sites belonging to the Late Mesolithic Ertebølle or EBK (5400-3900 BC) are coastal, totalling several hundred (Andersen 1993a). There is a long history of investigation of kitchenmiddens dating back to the middle of the nineteenth century and these are the most well known sites although there are several other types from flint scatters to stratified sites. At some kitchenmiddens, such as Norsminde and Bjørnsholm (Andersen 1991; 1993b), layers dating to the Early Neolithic Tragtbæger (TRB) or Funnel Beaker culture (3900-2900 BC) have been found overlying the EBK layers.

The perception that Star Carr was a winter base camp has shifted through the years to one of spring/summer occupation and now possibly back to winter again, but interpretations still vary somewhat. Andresen et al. (1981) suggested that the combined evidence implies occupation throughout the year, not continuous but rather short visitations, and that the site was used as a hunting stand and butchering station where animals were driven to be slaughtered, the location on a peninsula being ideal. Pitts (1979) saw the location of the site as important and suggested that it was probably used for leather working and hide tanning. If this was the case, he proposed the site would have been occupied in the summer, the reason for this being that the winter would have been far too cold for tanning. Other views as to the function, using artifactual and seasonality evidence, suggest Star Carr was a base camp (Clark 1954; Jacobi 1978; Mellars 1976), a butchering site (Caulfield 1978), and a hunting camp (Legge and Rowley-Conwy 1988).

The composition of EBK and TRB midden layers is usually clearly different. To the eye the EBK layers tend to be composed of oyster shell (Ostrea edulis), but other molluscs such as cockles (Cerastoderma edule), mussels (Mytilus edulis) and periwinkles (Littorina littorea) occur as well as the remains of terrestrial and marine animals, cultural artefacts and hearths. The TRB layers, in contrast, are made up of predominantly cockles, large amounts of burnt stones and spreads of charcoal with some remains of other animals and artefacts. Some oysters may also be found although they appear to be significantly smaller than those in the EBK layers.

From the evidence, several general points may be drawn regarding the interpretation of seasonality data: •

Caution must be used when considering ethnographic and ecological analogues because environments have changed through time and it is difficult to assess not only how humans would have behaved in the past but also how animals would have responded to their surroundings. The seasonal information obtained from one line of evidence does not give the overall seasonality of the site; it merely indicates the time of death of that particular species. Similarly, absence of evidence does not mean absence of occupation; some foodstuffs may be archaeologically invisible and some food may be eaten away from the main camp. The size of the sample being used for interpretation should be taken into account: a MNI (minimum number of individuals) of 1 or 2 animals is not as convincing as 30 or 40 all demonstrating one season of exploitation.

There may be reasons other than consumption that result in the appearance of faunal remains on a site. Both bone and antler can be used for artefacts, such as points or harpoons, and these may be collected and stored for long periods before they are worked. Alternatively some animals may have died naturally at a site.

Although at first sight it would appear that vast numbers of shellfish were consumed in the EBK it has been shown that these probably contributed only a small amount to the overall diet (Bailey 1975; Clark 1975). The number of other animals 3

CHAPTER 1 found at the larger sites tends to be great and includes ungulates, sea mammals, sea birds and fish (see Andersen 1995 for a extensive list of species). Different fishing technologies have also been discovered at waterlogged sites with excellent preservation conditions such as Tybrind Vig (Andersen 1985). Fish traps, hooks, leisters, harpoons, nets, lances, dugout canoes and paddles have all been found (Andersen 1995). Such abundant resources and sophisticated technology have contributed to the view that the Ertebølle culture was a highly complex society (Price 1985).

to be situated on islands or headlands which would have been prime vantage points for the exploitation of certain species, such as swans at Aggersund, or whales at Vænge Sø. Larger sites, however, such as Ertebølle, Bjørnsholm, Åmolle, Meilgaard and Norslund are all in more generalised sheltered locations, mainly in fjord interiors. It was noted that none of the larger sites had Neolithic occupation levels, while many of the smaller sites do, however, this has since been shown to be false for Bjørnsholm, which is one of the largest middens in the country and has Neolithic levels (Andersen 1993b).

Another indicator for complex societies is the presence of cemeteries and these have been found at Vedbaek Bøgebakken in Zealand (Albrethsen and Brinch Petersen 1977) and Skateholm in south Sweden (Larsson 1984), with the inhumations containing grave goods. There are some instances of violent death in these cemeteries, which may be the result of conflict between groups (Price 1996). Territoriality is inferred from the local distribution of some artefact types (Price 1985; Vang Petersen 1984) and artefacts with specific patterns of incised art are shown to have regional groupings, with some implements specifically from East Jutland and Funen bearing a sheaf of grain motif (Andersen 1980). Studies have also been made on a smaller regional scale (Andersen 1976; 1993b; 1995). In the Limfjord area the shell middens of Ertebølle and Bjørnsholm are seen as large, centrallypositioned sites, surrounded by smaller more specialised satellite sites. There is a distinct local group distinguished by the frequent use of amber and local variations of pottery and there is a higher frequency of multi-purpose artefacts than in other regions with a dominance of flake axes (Andersen 1995). There also appears to be a difference in the style of flint artefacts between Bjørnsholm and Ertebølle despite their contemporaneity, those made at Ertebølle being more regular and carefully made. In addition, there is a complete lack of Ertebølle sites in the Trend Å, the fjord between the fjord of Bjørnsholm and the site of Ertebølle, despite the fact that this fjord has been intensively surveyed and is about the same size and a similar habitat to the Bjørnsholm fjord (Andersen 1993b).

In terms of economy it has been demonstrated that these hunter-gatherer-fishers may have lived all year round at the coast because the resources were so plentiful and a model was constructed to demonstrate this year round availability, see figure 1.1 (Rowley-Conwy 1983; 1984). Bailey (1978) used the concept of economic territories when considering shell middens in Denmark, Spain and Australia. The seasonal data from Denmark was believed unlikely to be that of a truly sedentary economy, but this was defined as “a self sufficient community which occupies a site continuously throughout the year and draws its total annual subsistence from within the confines of a single site territory.” Within this definition the Ertebølle people were considered to be mobile-cum-sedentary with a high degree of residential stability on the coast (Bailey 1978, 51). More recently Johansen (in press) has taken a similar stance. Nielsen (1987, 240) on the other hand considered the ecological niches that were being exploited in the Ertebølle and described the sites as specialised towards hunting, gathering or fishing of particular species. Nielson therefore saw the Ertebølle as a mobile group: “The Ertebølle hunter-fisher-gatherer was thus extremely mobile and highly capable of adjusting himself to different environments. He performed a series of techniques that were complementary throughout the year and made him move with the seasons within a fairly large territory.”

Several different opinions exist on the degree of mobility of the Ertebølle people. Although no evidence for structures has been found near or within the middens despite extensive searches, especially at the sites of Ertebølle and Norsminde (Andersen 1991; Andersen and Johansen 1987) the Ertebølle hunter-gatherer-fishers are largely considered to have been sedentary. Madsen et al. (1900) were the first to describe the larger coastal sites as year-round occupations and Clark (1975) used large population size and site complexity to argue for sedentism among the Ertebølle. Rowley-Conwy (1983) used site size, economy, location, and the presence of overlying Neolithic deposits as indicators of whether a site was “temporary” or “permanent”. To categorise the middens in term of size, they were split into two groups according to volume of material. The larger sites, which may be several hundred metres long, were considered to be permanent sites and the smaller ones temporary sites. The smaller sites tended

A final important indicator of social complexity comes in the form of exotic goods. The appearance of ceramics and certain axe types in the late EBK deposits indicate contact and exchange with the Danubian farmers in the south (Price 1985) and the presence of shaft-hole axes, made of Polish amphibolite have been interpreted as status symbols for the Ertebølle (Fischer 1982). This evidence of contact with farmers in the south, spanning a period of about 1000 years, has generated a great debate as to why the Ertebølle took so long to adopt agriculture.

4

SEASONALITY STUDIES

cod mackerel eels small whales harp seal grey seal pups fur animals land mammals swans ducks hazelnuts acorns fruits plants cockles mussels oysters J

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Figure 1.1. Proposed resource availability schedule for the Danish Ertebølle (adapted from Rowley-Conwy 1984)

The Transition to Agriculture Several different explanations have been proposed for the eventual adoption of agriculture to Denmark. Detailed overviews may be found in Price (1996, 2000). In summary there are four main hypotheses: 1. Invasion One of the first explanations as to why the transition took place was that agriculture was a product of invasion. Until the 1960s it was thought by archaeologists such as Becker, that the EBK and TRB ran parallel to each other (Madsen 1987). Troels-Smith on the other hand considered that some of the TRB was part of the Ertebølle culture and there was another part of the TRB that invaded (Horwitz 1973; Troels-Smith 1953 cited in Madsen 1987). A re-assessment of the data and many new radiocarbon dates (e.g. by Tauber 1972) led most archaeologists to believe that the TRB followed on from the EBK, at the same time revealing how late it occurred in comparison with Central Europe. Becker (1973) and TroelsSmith (1982) have maintained the view that an invading population was responsible for agriculture appearing in Denmark but it is now generally thought that agriculture was adopted by the indigenous Ertebølle communities. 2. Population pressure/demographic stress Population pressure was used by Clark (1975) to argue for the transition to agriculture. Even if it is not stressed directly, other explanations such as ecological or environmental changes point indirectly to demographic stress (e.g. PaludanMüller 1978; Rowley-Conwy 1983; 1984; Zvelebil and Rowley-Conwy 1984). Some studies have suggested an increase in population through the Mesolithic (Petersen 1973) but there are problems in assessing such a phenomenon. Difficulties arise in calculating the total number and size of

Mesolithic sites, in judging the appropriateness of ethnographic analogies for site and population ratios, and in defining the length and continuity of occupation at sites. The differences between the TRB and the EBK would also be difficult to quantify because of the physical nature of the sites. The bulkiness of shellfish on the Mesolithic middens is obviously going to make these sites appear larger. Other approaches such as the analyses of human skeletal remains have been conducted and these have shown no evidence of stresses but rather that the EBK were robust and there are few pathologies (Bennike 1993). To date there does not appear to be obvious evidence for rising population preceding the transition or immediately afterwards (Price 1996). 3. Social change Many papers have rejected changes in population pressures and instead have looked to changes in social behaviour and ideology as a way of understanding neolithisation. This includes the adoption of agriculture as being a response to increasing desires for status and prestige and the accumulation of surplus and wealth (Fischer 1982; Jennbert 1985), and a change in social relations and organisation (Thomas 1988). Hodder (1990) suggests a change in ideology for the farmers in the south that was acceptable to the Ertebølle culture and was adopted along with agriculture and Price (1996) forwards an increase in status differentiation and trade. 4. Resource availability A number of papers have argued for a decline in resources, either through population pressure or through environmental change prior to the transition to agriculture (Larsson 1987; Madsen 1987; Paludan-Müller 1978; Rowley-Conwy 1983, 1984, 1985; Zvelebil and Rowley-Conwy 1984). The transition to agriculture occurs at the same time as the change from the Atlantic to the Sub-Boreal. The Sub-Boreal may have been significantly cooler and drier, and there was a regression of the Litorina Sea at this time. Changes in sea levels and 5

CHAPTER 1 salinity have been used to argue that the marine animals, which were so heavily exploited, would not have been so plentiful.

the fact that oysters are so much smaller in the TRB layers. Rowley-Conwy (1984) suggested that as the oyster was no longer able to fill the gap in the annual schedule and other marine resources may also have declined it was necessary to seek an alternative source of food production, and agriculture was adopted.

Rowley-Conwy’s (1984) model of seasonal procurement strategy is the most frequently used in this debate. By ranking the resources that would have been available in terms of possible return rates in calories per hour, it has been shown that shellfish and fruits could be considered less attractive than other resources. They appear to have a low productivity per hour of work and have been shown by Bailey (1975) to only contribute a very low part of the overall diet, usually less than 10%. Rowley-Conwy (1984, 306) suggests, however, that oysters were in fact more essential to the diet than the ranking results suggest, due to the fact that “most known western Ertebølle coastal sites are made of oyster shells”. This suggests that something was counteracting the ranking of resources – perhaps a heavy seasonal usage of oysters.

The latter approach, that is resource availability, is of most interest in this volume because seasonality information is used directly. Although Price (1996, 2000) has dismissed the arguments for a decline in resources as an explanation for the transition to agriculture it is still frequently quoted and favoured (e.g. in discussions at the Mesolithic 2000 conference in Sweden).

An Evaluation of EBK Seasonality Studies

Seasonal scheduling and the role of the oyster were assessed by determining the seasonal availability of resources, see figure 1.1 above. For instance: • cod and mackerel were likely to have been available in summer and eels are more concentrated in number and nutritious in autumn (although they can be caught all year round) • nuts and acorns are available in September and October (storage may have been more problematic than often proposed) • ungulates would have been most nutritious in the autumn losing condition through the winter • small whales may have been hunted in December and January (when they move in groups) • some species of seal also gather together in the winter; birds such as duck and swan are migratory and tend to over-winter in Denmark leaving in the spring. It was therefore proposed that the lean period of the year would have been the spring. At this time, oysters are at their best in terms of calorific return rate and oysters may have been essential in “plugging the gap” in the seasonal resource cycle (Rowley-Conwy 1984). It has been argued that at the time of the transition to agriculture changes in water levels and salinity caused by the Late Atlantic Litorina sea regression reduced the availability of oysters. Oysters are susceptible to such changes, particularly if they are already at the limits of salinity tolerance and environmental pressure may account for J

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Although there are many elements to the middens both in the EBK and TRB layers, the faunal remains make up the majority of the data set. It has been shown that seasonality studies contribute to interpretations, and either overviews are made to investigate issues such as sedentism, scheduling of resources and the transition to agriculture, or research is carried out on a smaller scale in order to interpret the seasonality of a particular site. Returning to the problems highlighted at the beginning of this chapter I would argue that there appear to be 3 main problems with seasonality assessments in the study of the Ertebølle. • • •

Many assumptions regarding human predation and animal behaviour are used Often very small sample sizes are used in the interpretations The evidence for all-year-round scheduling of resources is generally unconvincing

The comprehensive reports on mammal, bird and fish remains at Bjørnsholm will be used below to demonstrate these points (Bratlund 1993; Enghoff 1993). A chart has been constructed to show the seasonal evidence for the presence of species, figure 1.2.

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birds fur-bearing wild boar roe deer roe neonates red deer calf saithe, cod eel mackerel Figure 1.2: Seasons of exploitation for the resources at Bjørnsholm (data from Bratlund 1993 and Enghoff 1993) 6

SEASONALITY STUDIES

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birds fur-bearing wild boar roe deer red deer calf saithe, cod eel

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MNI 1 2 9 or 10 7 or 8 1 11, 10% 56%

mackerel

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Figure 1.3: Revised seasons of exploitation for the resources at Bjørnsholm In many site reports or overall studies of seasonal scheduling, certain animals are assumed more likely to have been hunted at a particular point in the year because they are of greater value at this time. An example being the animals termed “fur bearing” such as badger (Meles meles) fox (Vulpes vulpes), wolf (Canis lupus), dog (Canis lupus f. familiaris), wild cat (Felis silvestris), otter (Lutra lutra) and pine marten (Martes martes). These are generally seen as indicators that the site was occupied in the winter, their furs being more desirable, and often at their best at this time (e.g. Andersen 1974; Andersen and Johansen 1987; Rowley-Conwy 1981). Although this may be true in many cases, it should not always be taken as read. These animals may have been procured for meat as well as fur. Badgerham is considered a delicacy in Denmark today and dogs and rodents are eaten in other parts of the world (Bratlund 1993). The fur bearing animals from the well preserved underwater site of Tybrind Vig have been analysed for cut marks by Trolle-Lassen (1987) and the cut marks on the otters and wild cats indicated that meat, as well as fur, had been exploited. It was not possible to assess the season of procurement for these species but what is significant here is that otter fur is valuable regardless of season, as shedding of hair is not restricted to a short time period (TrolleLassen 1987). At Tybrind Vig it was found that pine martens and polecats were only killed for their pelts. From the age structure of these populations it was stated that the pine marten had actually been killed in the autumn, between September and November and that the polecats had been trapped during the autumn and winter. At Bjørnsholm however, a minimum number of 2 pine martens were identified but one of these appeared to be only a few months old suggesting a summer kill (Bratlund 1993). The minimum number of species identified is often very small. At Bjørnsholm all the bird bone analysed only had MNI (Minimum Number of Individuals) counts of 1, with the exception of the swan, which had 2. The bird bones found at these sites are also often used as an indicator of winter occupation. The whooper swan (Cygnus cygnus), barnacle goose (Branta leucopsis), gannet (Sula bassana) and blackthroated diver (Gavia arctica) are all thought to have been present in the winter, assuming that their patterns of migration in the Atlantic climatic period were similar to those of today. However, it is very difficult to identify between a

mute swan (C. olor) and a whooper swan (J. Stewart pers. comm.) and this is important for interpretation because the mute swan would have been present at the site all year round (Heinzel et al 1974). Similarly the blackthroated diver breeds in the summer in south Sweden and may well have bred in Denmark earlier in the Holocene. More exact evidence as to their time of death may occasionally be available. At Bjørnsholm a bird bone, not identified as a particular species but recognised as being the size of a goose, shows medullary bone deposits. The medullary bone is a specialised bone which serves as a calcium store used for the production of egg shells during the laying period and will occur in females at specific times of the year (Lentacker and Van Neer 1996). This therefore indicates a time of death in the spring just before the breeding season (Bratlund 1993). However, it is possible that the people occupying the site may not have hunted these birds, instead the birds may have been hunted by other predators, or died naturally and were perhaps washed up by the sea. The age structure of the wild boar fauna (MNI = 9 or 10) suggests that these animals were being hunted between March and June, but some may have also been killed in the winter. The total MNI count for roe deer is 7 or 8. From age structure and unshed antler the adults appear to have been killed between April and October, and the neonates and juveniles between June and August. The MNI count for red deer is 4, and although the presence of a young calf suggests a kill in June or July the antler remains for the adult deer are inconclusive with regards to seasonality. There were a large number of fish bones at Bjørnsholm. A total of 11490 fish bones have been identified from the Mesolithic deposits showing a dominance of eel (Anguilla anguilla) bones (56%). This proportion may well have been much greater as eel bones are of a fatty nature and therefore do not survive particularly well. Growth ring analysis was performed on eleven otoliths from saithe (Pollachius virens) and cod (Gadus morhua) by an expert, E. Steffensen, from the Danish Institute for Fisheries and Marine Research. The results showed that these fish had been caught in late summer and autumn and if the results had been taken from recent fish their death would have been interpreted as September (Enghoff 1993). These otoliths were lying next to a lot of eel bones and these too have been interpreted as mainly being caught in the autumn. At this time they migrate from 7

CHAPTER 1 freshwater streams to the sea en masse and the populations of the migrations are mainly made up of females. This correlates with the data in the midden, most of the eels being over 50cms in length, an indication that they are female. Mackerel (Scomber scombrus) was also found in the deposits. This is a seasonal fish and would only have been available in the summer. It is even stated that fishing was probably not carried out in the winter because of the regular occurrence of mackerel throughout the midden (Enghoff 1993, 116). The greater weaver (Trachinus draco), cod, saithe and spurdog (Squalus acanthias) are also easier to catch in the summer as only at this time do they come near to the coast (ibid.).

by other mammalian predators, so that the most probable reason for their presence on a site is human activity. Furthermore, the interpretation of the seasonal exploitation of mammals, fish and birds often demands an understanding of seasonal movements and hence inferred availability. Shellfish, however, are available all year round and therefore evidence for seasonal selection is dependent on factors other than availability (Deith 1983).

To sum up the seasonality assessments for Bjørnsholm it can be said that there is fairly firm evidence for occupation in the summer and early autumn. This is based on the otolith analysis, evidence of migratory fish and possibly some of the terrestrial mammals. There are possible indicators of exploitation in the winter and spring but the evidence is far from persuasive. Figure 1.3 has been modified showing how different a seasonality chart may look if some lines of evidence are used with more caution. The dotted lines are assumptions that have been made and the MNI column shows that in any case these are based on very small sample sizes.

This volume demonstrates how seasonality information can be obtained from oyster shell using a modern control sample and then archaeological specimens. As the analysis of seasonality has never been attempted before for the European oyster the first part of the volume describes the methodology. Firstly, it is important to be familiar with the ecology of the oyster. Ambient temperature, spawning, food and so on affect growth of the animals and changes in growth are reflected in the shell structure. Chapter 2 details some of the more relevant aspects of the annual biological cycle of the oyster which will in later methodological chapters be referred to in order to interpret the incremental growth structures of the shell. As well as being familiar with the annual life cycle of the oyster it is important to have a modern control sample. Changes in growth through the year can then be monitored and the month or season when annual lines are formed may then be ascertained. The modern controls are then used as an analogy for the archaeological shells. Chapter 3 reflects on the use of modern controls as an ecological analogy and the problems that may be incurred. The modern controls used in this study are then described and methods of sub-sampling for analysis outlined.

Outline of the Volume

This data could now be re-interpreted to suggest a season of occupation of spring, summer and autumn, with emphasis on summer and autumn. There is no convincing evidence for winter occupation. However, this does not necessarily mean that the site was unoccupied in the winter. There are several lines of evidence that have not been explored, notably the shellfish. Plant foods tend to be absent in the archaeological dataset but it is probable that they were consumed, and storage and drying of foodstuffs may also have taken place. Of course absence of evidence is not evidence of absence!

Chapter 4 described the methods that can be used in incremental analysis and outlines the experiments with methodologies that were tried and tested. Thin sectioning was finally used for this particular analysis and a full description of the technique is given. This technique was applied to the subsampled modern control and the incremental growth structure analysed. Chapter 5 describes the results and observations made when identifying annual lines and disturbance line and anchoring these to points in the yearly cycle of growth. The method of interpretation relies on observation by eye of seasonal markers in shell structure, rather than by measurement and as this could be argued to be subjective it is necessary to conduct blind testing. Chapter 6 describes blind testing experiments carried out on the control sample of known seasonality. Because it was felt that the methodology worked and the blind testing demonstrated that interpretation was possible a selection of archaeological shells from 6 kitchenmiddens was made.

This re-interpretation of the data from Bjørnsholm can be achieved easily, and demonstrates the flexibility and problems of seasonality studies. This is unlikely to change anyone’s view or an established opinion on the sedentism or mobility of the Ertebølle but it should have highlighted the need for a fresh line of evidence. Part of the problem results from the nature of the remains. The bone report is based on half the excavated sample and most of the bones are very fragmentary. Only 20% of this sample could be identified to species level and only a fraction of this information is useful for seasonal interpretation (Bratlund 1993, 100). Another problem is that these analyses rarely give spatial and temporal resolution of seasonal procurement. The eleven otoliths which were analysed at Bjørnsholm were all taken from one area of the midden but it is possible that otoliths found in other parts may give different seasonality readings. Similarly, over the thousand radiocarbon year span of the midden it is quite possible that occupation and resource procurement patterns may have changed.

The sites and sampling of the shells are discussed in Chapter 7 and the results of thin sectioning presented in Chapter 8. Chapter 9 brings together these results and the resulting questions into a discussion of sampling and seasonality for the Ertebølle period and for the transition to agriculture and avenues for future research are suggested.

The fact that oysters are the primary component of the middens makes them an ideal subject for Ertebølle seasonality studies in that large sample sizes may be used, especially as the hinge area which stores the incremental record survives well. They are also relatively immobile and are not exploited

8

CHAPTER 2

The Oyster

Incremental growth analysis of molluscs involves studying the structure of the skeleton (or shell) in order to identify patterns in shell deposition which may relate to changes in the environment. For such a change to be registered the physiology must be altered. A metabolic response to a change in the environment may, for instance, result in a biochemical response in the mantle, the part of the animal that is responsible for shell construction. This is also known as ontogenetic growth which has been defined as “the life history of an individual organism as it is preserved in mineralised or otherwise refractory tissues” (Rhoads and Lutz 1980, 3). Markers in the shell structure such as breaks in growth (visible as lines) or alternating bands (perhaps dark and light in colour) can be linked to certain environmental events by using modern samples as a control. Before using a modern control however, it is important to be aware of the type of changes that may affect an oyster’s growth. This chapter outlines the relevant biology and physiology of the oyster.

CHAPTER 2 the seasonality of the European oyster, Ostrea edulis. It has been suggested that by using new techniques developed for the American oyster on Ostrea edulis “…it may be possible to better understand the extensive Ertebolle middens of northern Europe and evaluate additional hypotheses of coastal resource use.” (Custer and Doms 1990, 159). This is the intention of this volume, however, before conducting such research it must first be recognised that Ostrea edulis grows and responds to its environment in its own unique way not paralleled in any other species, including Crassostrea sp..

Incremental Growth Analysis Although experts very often succeed in identifying lines or bands in the incremental growth structure that can be related to seasonal events, or perhaps temperature change, the exact reason why these occur is not always so apparent. Some species of bivalve exhibit incremental lines on a daily or subdaily basis (e.g. Coutts 1970; Deith 1983) for which Lutz and Rhoads (1977) produced a theory of growth formation. This suggested that during aerobic metabolism, when the valves are open, molluscs deposit calcium carbonate in the form of aragonite or calcite together with organic material, which results in shell construction. When the valves close, concentrations of dissolved oxygen fall and levels of succinic acid rise. It was thought that the acid would be gradually neutralised by the dissolution of the shell and this alternate deposition and dissolution was believed to produce the banding.

An obvious difference between the species is the physical appearance, Crassostrea sp. being longer and deeper with a coarse shell and Ostrea edulis rounder and flatter. Both can withstand variations in salinity but Ostrea edulis is much more susceptible to changes. It cannot tolerate salinities below 23 ‰, and this figure needs to be higher for larvae to survive, whereas Crassostrea sp. can live in almost fresh water. Both species can survive in turbid waters but Ostrea edulis needs a firmer substrate with little silting on which to settle due to its flatter morphology. In terms of sex, Crassostrea sp. starts off as male but later the population splits into those that remain predominantly male and those that remain female. Ostrea edulis on the other hand changes sex after each spawning event. When the animal is female Ostrea edulis incubates the fertilised eggs for one to two weeks before ejecting them into the sea, unlike Crassostrea sp., where the female ejects the eggs into the sea where fertilisation and development takes place (Walne 1974, Yonge 1960). These fundamental differences will obviously affect the way the animals grow and deposit shell resulting in the incremental growth record. It is therefore very important that an analytical technique, such as that used on the American oyster, is not simply transferred to Ostrea edulis, or any other species, without 1) prior understanding of the biology and physiology of the species and 2) the examination of a modern control sample.

This explanation has often been used in archaeological studies (e.g. Fitzhugh 1995), even for species which do not exhibit clear daily or sub-daily banding such as the oyster (Lawrence 1988; Kent 1988, 62). It has, however, been shown that although anaerobiosis is almost certainly responsible for certain internal increments the possibility still exists that most internal growth increments are not directly related to it. Alternative modes of formation may be dependent on variations in the proportion of secreted organic matrix versus calcium carbonate, or changes in the microporosity or ultrastructure of the deposited mineral that occur independently of anaerobiosis (Carter 1980; Gordon and Carriker 1978). It could also be the case that other factors such as salinity might influence the proportion of shell organic matrix (Carter 1980). Richardson et al. (1979) conducted experiments on constantly emerged cockles, which according to the anaerobiosis theory should not have produced banding at all. Growth bands were however identified and although the banding was less distinct and regular, the average number of bands in the shell layers did correlate with tidal periods. The formation of these bands was explained as either due to gravitational force, food availability or an endogenous rhythm in shell growth.

Biology and Physiology of Ostrea edulis This section principally uses two seminal studies of oysters to describe the biological and physiological functions of Ostrea edulis, which are of relevance in later chapters. These studies are “Oysters” by Yonge (1960) and “Culture of Bivalve Molluscs” by Walne (1974), unless referenced otherwise.

In the case of Ostrea edulis, no finer resolution than annual lines (and the occasional disturbance line) has been made (Richardson et al. 1993). This work was carried out by marine biologists in order to age oysters. Clearly defined “wintergrowth” lines were identified in the hinge area of the oyster, which were thought to form in the spring. It is likely that these lines form due to a resumption of growth after the hibernation period in the winter. As the water temperatures rise the metabolism of the oyster will increase and the mantle will start to deposit calcareous deposits on the margins of the shell once more. “Other” lines were identified which did not conform to the characteristics of the winter growth lines.

Ostrea edulis is one of about 10 000 species which belong to the bivalvia group of the phylum mollusca (Wye 1991). The outer shell of the bivalve is comprised of two valves that are joined at their hinges by a supple ligament. These valves open and close by the use of strong interior muscles. The fossil record for bivalves goes back to the Ordovician, and oysters similar to modern species can be found in the Jurassic and Cretaceous periods. It is thought that oysters were originally stocky animals with a dorsal shell covering their backs and a muscular foot, which enabled movement. Evolution led to the shell becoming bent down the mid-line of the centre of the back, which eventually became two shells hinged on the dorsal surface. The shell became a protective structure, decreasing the need for movement. As the oyster became sedentary, much of the sensory system was not needed and the head

Although studies of the skeletal growth record have been applied in archaeological seasonality research over the last three decades, including work on the American oyster, Crassostrea virginica, there has been no attempt at assessing 10

THE OYSTER disappeared, as did the foot. Nutrition was brought to the animal by an elaboration of the respiratory gills that pump food-bearing water through the shell (Yonge 1960).

to be a close correlation as there is with some marine animals (Korringa 1957). When an oyster is in its male phase the sperm is ejected into the sea through its exhalent chamber. As a female, however, the eggs are passed through the water tubes in the gills and into the inhalent chamber. The eggs are fertilised here by sperm, which is brought in by the feeding current and they are retained here for protective purposes, for about one to two weeks before being discharged into the sea. When oysters are incubating eggs they are described as being “white-sick”, “grey-sick” and finally “black-sick” due to changes in the pigment in the digestive tubules, and this is an indication that they are not good to eat.

There are many species of oyster in the world today. Ostrea edulis Linnaeus (the European flat oyster) is native to Britain and northern Europe but imported species also grow in these waters. Crassostrea angulata (the Portuguese oyster), Crassostrea virginica (the American oyster) and Crassostrea gigas (the Japanese or Pacific oyster) all now either grow naturally or are farmed in Europe. Ostrea edulis is round and not very deep. The right valve is flat, with laminae usually of a brown/yellow colour and this sits on top of the left (lower) valve, which is cemented onto the firm substrate. The lower valve is cupped and foliaccous, usually white with streaks of pink and purple, although in some environments the valves may be green or yellow. Often the surfaces of the upper valves are covered with barnacle shells, coiled tubeworms, or the growths of sea squirts, hydroids, sea-mats and seaweeds. The interiors of the valves are shiny white.

According to Walne (1974) 1 year old oysters produce c. 100 000 larvae, 2 years olds 540 000, 3 year olds 840 000 and 4 year olds 1 100 000. By the time the larvae are ejected into the sea they have developed protective shell valves. They have a velum, or swimming organ, which is a circular lobe of tissue bearing a ring of cilia (hair-like vibrating organs), by which they are able to swim and feed. They alternate between swimming fairly rapidly upwards and sinking back down. The larvae remain in this developmental stage for one to two and a half weeks, according to the prevailing temperature. When the larvae reaches the stage of metamorphosis the shell changes from a “D” shape to the characteristic mature shape and a ciliated foot and black eyespot appear. This is the point when mobility is lost and the internal organs are modified for the change to a sedentary existence. The velum is retracted and the foot is used to explore.

Ostrea edulis is a sub-littoral species. Oyster beds may be partially exposed at low tides but the majority of adult animals remain permanently submerged in shallow water. Excessive exposure at low tides leads to a drop in growth rates and Walne (1958) has shown that growth ceases if oysters are exposed at low tide for more than 30 per cent of the time. Analysis of growth lines of oysters in wild populations by Richardson et al. (1993) showed that the maximum life span of oysters on natural beds in England is up to 14 years with an average age-range of 2 to 6 years.

After a couple of days a suitable resting location is found and the larvae stops crawling and rocks to and fro on one spot. It squeezes out a drop of cement from the byssal gland at the base of the foot and then applies the left, lower shell to the cement. This sets within a few minutes. Within 48 hours the velum, foot, and eyespot and anterior adductor muscle disappear, the mouth moves through an angle of 90 degrees and the posterior adductor muscles move to a more central position. Gills appear, the mantle becomes more extended and the two valves grow out parallel to the surface to which the oyster has attached itself. Within 3 or 4 days the basic adult body plan has formed and the larvae is now known as “spat”.

Reproduction When the oyster first reaches sexual maturity, usually in its first summer, it normally develops as a male. The reproductive organs are very simple branching tubules, the lining producing eggs and sperm. After spawning, the oyster tends to change sex, and this will continue throughout its lifetime. The change from female to male state is rapid and is completed within days of the eggs being discharged. The change from male to female, however, takes a period of weeks due to the fact that the formation of eggs demands the production of a great deal of yolk, needed to supply the needs of early development. It has never been noted that Ostrea edulis has functioned as both sexes at the same time.

The Animal

Water temperature and food supply will determine the number of times the oyster will reproduce in the year. In Britain, oysters tend to spawn twice during the summer months, once as each sex. Occasionally they may function twice as each sex if conditions are highly favourable. No development of the reproductive organs takes place below a certain temperature, and oysters may lie undifferentiated or dormant in either the male or female phase during the winter months.

The animal within the shell can be seen in figure 2.1. Like most animals it has a mouth, stomach, heart, intestine and anus which are only parts of the complex circulatory, digestive and nervous systems. In addition it has an adductor muscle that controls the opening and closing of the valves and this is divided into two parts. The quick muscle is responsible for closing the valves rapidly when the animal is disturbed and the catch muscle can keep the valves in a closed position for long periods against the elasticity of a ligament attached to the hinge. To open the valves the adductor must be cut.

Spawning occurs when the reproductive organs are ripe. This will usually occur when temperatures reach 15-16° C but in fact higher temperatures are needed for successful incubation and growth after the larvae are liberated. It has been suggested that there is a connection between spawning and the spring tides of the new and full moons although there does not appear

Beneath the valves the mantle totally covers and protects the animal. The mantle is flat except for the thicker margins, which contain muscles and a pallial nerve, and these have three parallel folds. The mantle plays several important roles in the life of the oyster. The inner mantle fold is largest, most muscular and mobile in order to control the inflow and 11

CHAPTER 2 outflow of water, the middle fold has tentacles and is sensory, and the outer fold performs the shell formation.

passing through the mantle cavity. During periods of closure, however, oysters build up an oxygen debt that has to be repaid when pumping restarts. Below a certain temperature oysters go into a state of hibernation when respiration and heartbeat may cease and ciliary action will be lowered. Ostrea edulis appears to be very sensitive to changes in the temperature and a sudden shift either way may result in a reduced up-take of oxygen, sometimes taking several days to become adjusted. Oysters of about three and a half inches can filter two and a half gallons of water an hour at a temperature of 15° C (Yonge 1960, 30) and this will increase by about 20-25 % at temperatures of about 20° C. The major role of the water filtering system is undoubtedly feeding but it also carries away waste products from the alimentary canal and the kidneys and brings a supply of oxygen. This filtering role is obviously crucial for maintenance and survival of the oyster and it should be noted that the rate of filtering is affected by temperature, velocity, movement of water and concentration of particles which fluctuate on a seasonal basis (Walne 1974, 21).

Shell Structure The fibrous insoluble protein, conchiolin, forms the basic structure of mollusc shells into which calcium carbonate from the sea is incorporated. The two crystalline forms of calcium carbonate in shells are aragonite and calcite. Aragonite can occur as either prismatic, nacreous or porcelaneous shell.

Figure 2.1: The general appearance of Ostrea edulis lying in the left valve after the removal of the right valve and mantle lobe (after Walne 1974; Yonge 1960).

Filtering and Feeding The mantle cavity is divided into a large inhalent chamber and a small exhalent chamber. The gills in the inhalent chamber are used for feeding and they are made up of crescent shaped plates covered in ciliated filaments. Water passes through the inhalent chamber by the movement of the cilia, through the sieve-like gills and into the water tubes where it flows into the exhalent chamber and out of the cavity. Filtering through the gills allows microscopic plant cells, plant plankton, nanoplankton and oxygen to be removed by the oyster. The food is massed in strands of mucus, which are transported by cilia to the palps and then the mouth. Large unwanted masses, pseudo-faeces, are caught in tracts in the palps and ejected through the inhalent opening. Prolonged excessive quantities of suspended material in the water may choke the feeding mechanism and in turbid waters the filtering activity leads to a rapid accumulation of mud which may also choke the animal.

Figure 2.2: Section through an oyster shell, after Yonge (1960) Key: A: ligament/ligostracum, B: adductor muscles, C: horny prismatic scales, D: hard sub-nacreous layer, E: chalky deposits, F: chamber Calcitic crystals occur in either prismatic or foliated microstructures and this type of shell is harder, less dense and less soluble than aragonite. (Claassen 1998). In most bivalves the shell is composed of the periostracum, prismatic layer and the nacreous layer, figure 2.2. The periostracum is a thin organic layer, horny in appearance, on the outer part of the shell. Initially it covers both valves and the ligostracum (hinge muscle) but in oysters it tends to be thin and is often worn away. The outer, prismatic layer is confined to the upper (flat) valve of the oyster. It forms the flattened rather horny scales, although there is only about 5 to 6% organic matter within them. These scales are not entirely rigid to allow the 2 valves to make perfect contact at the margins when the valves close. The greatest part of the shell is the sub-nacreous layer of

The small particles that reach the stomach are either digested using enzymes or some are small enough to be ingested within the cells. Tracts of cilia also pass unwanted particles to the intestine and rectum; faecal matter is consolidated and then passed through the anus into the exhalent chamber where it is discharged with the exhalent current. Colourless blood and the circulatory system carry the products of digestion and the oxygen from the gills to all parts of the body. Under favourable conditions the oyster will remain open and will pump water through its system all day. A pumping oyster removes about 5 percent of the oxygen content of the water 12

THE OYSTER calcite, or calcite-ostracum, composed of horizontal sheets. Patches of brown and green horny conchiolin may also become embedded in this layer. These patches appear to be laid down for reinforcement and repairing of the shell.

The oyster shell itself is a rich habitat (Korringa 1951). A large number of macroscopic and microscopic plants live on the valves, which serve as food for both sedentary and mobile animals. The oyster also acts as a shelter for certain species that dwell between the laminae of the right valve or in the crevices of the left one. Some of this epifauna is harmless but others cause stress to the oyster, or compete for space and food.

Opaque white masses may also form and these consist of chalky deposits that are porous and contain sea water. They are crystalline and are of the same nature as calcite-ostracum but are simply less dense. This deposition of chalky material can alter the internal contours of the shell, which may aid in the functioning of the oyster. In addition, chambering may occur, especially in the lower valve of older oysters. The mantle surface becomes stretched across the deeper areas of the cupped valve and sub-nacreous material is laid down with spaces in between. This may be due to shrinkage of the mantle, caused by a change in water salinity, when the tissues become dehydrated, or body-size reduction after spawning. Under these conditions a thin layer of organic conchiolin is formed, followed by sub-nacreous material.

Starfish (Asterias rubens) can attack both adult oysters and spat. They use their arms to grip the valves and by means of hydrostatic pressure in their suckers pull the valves apart. The stomach of the starfish then protrudes through its mouth and between the oysters’ valves. The common shore crab (Carcinus maenas) can also be a danger to oysters, especially younger oysters, as it is able to break away the margin of the shells with its claws. Drills, such as the rough tingle or sting winkle (Ocenebria (Murex) erinacea) which is native to Britain, and the introduced oyster drill or whelk tingle (Urosalpinx cinerea) bore into the shells and scoop out the living flesh. As the oyster thickens with age however, the risk of drilling diminishes and there is little mortality in oysters over 2 years of age. In addition, oysters may suffer from minute parasitic snails (Odostomia eulimoides and Chrysallida obtusa) which settle on the edge of the shell and probe into the mantle margin with a long proboscis, sucking out the blood and soft tissues.

External Stress Factors In the yearly life cycle the oyster has been shown to respond largely to seasonal changes in environmental variables, such as temperature, which regulate events such as summer spawning and winter dormancy. Environmental conditions do not always follow a pattern, however, and the oyster may be subjected to random changes in temperature, salinity or food supply as well as predator attacks.

Certain predators settle on the shells of the oysters and bore into them. The sponge, (Cliona celata) does not feed on the oyster but on minute nanoplanktonic organisms. It bores in for protection sometimes permeating the whole shell with holes (Nield 1995). If the sponge bores through the shell into the inner cavity the mantle must respond by depositing greenish yellow conchiolin over the perforations. If the sponge is especially vigorous, the oyster can become exhausted by the continual effort of conchiolin secretion. Bristle worms (Polydora sp.) can cause similar problems too. Polydora ciliata grows to about an inch and may be found between the horny scales of prismatic material on the upper flat valve. It also settles on the lower cupped valves where it produces mucous tubes, to which mud adheres, and it lives in these or bores into the shell. Again, if they bore right through the shells, the mantle of the oyster attempts to cover the holes in conchiolin.

Extreme cold can cause detrimental effects, either due to the oysters freezing, or due to a sudden thawing of snow resulting in estuaries being inundated with fresh water, dramatically lowering the salinity of the water (Nield 1995). This phenomenon occurred in the winter of 1939-40 when the temperature over the oyster beds in the Thames Estuary and along the East Coast dropped to 0°C causing ice flows on the shores. This resulted in over half the population of oysters being destroyed from either the effects of a reduced salinity or paralysis of the adductor muscle. In January 1953, exceptionally high tides in the south of the North Sea caused great floods in the Thames Estuary and Holland. Embankments were breached and a combination of burial beneath silt and high levels of silt in the water led to a mortality of up to 40% (Yonge 1960). Seasalter oyster farms, Whitstable, also suffered a natural devastation of their oyster beds in the winter of 1995 when storms hit the Kent coast and destroyed all the beds of Ostrea edulis (Martin Convery pers. comm. 1996).

Other types of worms are not predators but parasites or competitors for food. Polydora hopura is a parasite which does not bore into the shell but establishes itself within the shelter of the valve margins, placing its body between the shell and the mantle. The mantle seals off the worm and accompanying mud and this forms a blister. As the worm grows it breaks through the base of this and so the blister tends to extend further into the shell. This is a serious challenge to the oyster due to the amount of energy that it must expend in the additional formation of shell.

Natural epidemics have, on occasion, wiped out large populations of oysters. In 1920 and 1921 the oyster beds in England, France, Holland, Germany and Denmark were badly affected although the cause was not absolutely clear (Orton 1937). It is possible that the large numbers of deaths were caused by the highly lethal, minute flagellate protozoan, Hexamita, a parasite which flourishes in low temperatures and overcrowded conditions. It occurs as a cyst or in the blood cells of the oysters, and degeneration and inflammation occur with accompanying invasion of bacteria.

Competitors do not eat or exploit oysters in any way but there may be continuous rivalry for food and space. One such example is the slipper limpet (Crepidula fornicata) which is also immobile and feeds, as oysters do, using ciliary currents 13

CHAPTER 2 in the gills. It tends to compete more for space than food. This is also true for the introduced Australasian acorn barnacle (Elminius modestus) which competes for space at times of spawning, the larvae settling about the same time as the oysters. The barnacle, however, tends to outgrow the oyster spat and the latter is consequently smothered.

Monitoring the Life Cycle A number of events occur in the yearly life cycle of the oyster. Some of these are seasonal and to a degree predictable. The growth of the oyster will slow down in the winter and shell will almost stop forming. In the spring, with the rise in temperature, the oyster begins to grow again until the summer months when temperatures prompt spawning. The stress of spawning, especially the energy expended in producing eggs may cause the condition of the oyster to deteriorate, again perhaps causing some cessation of growth. Other causes of stress are not timed to certain months or seasons. These include natural events such as storms or predator attacks. Again growth may be affected, especially if the oyster uses a lot of energy in making conchiolin to cover holes. Other events such as disturbance and cessation of growth may also be recognised. Although the actual mechanisms may not be fully understood, changes in growth may be monitored by collecting a modern sample of shells at periodic intervals for over a year. The month or season when annual lines are formed may then be ascertained.

14

CHAPTER 3

Modern Control Sample

A modern control sample is a critical part of a study such as this because the observations made are then used as an analogy for the archaeological shells and are therefore used in forming interpretations. Using a modern control sample will always have some limitations, as does any analogy which is used to interpret the past. Irregularities in the modern control may lead to a whole series of misconceptions. When using analogy in archaeology, Hodder (1982) suggests that to avoid charges of unreliability we need to increase the number and range of points of comparison between past and present. When applying an ecological analogy it is necessary to carefully consider the sample size of the modern control and how points of comparison can be made between modern and archaeological samples. The first section of this chapter illustrates some of the problems with using modern controls that have arisen in the past and considers approaches to sample size and sample location, with reference to how these may affect interpretation. Following this, the modern controls used for this study are presented.

CHAPTER 3 This history demonstrates just how misconceptions may be made and shows how important a thorough understanding of a modern control sample is. In the study of shellfish, there is at least the practice that the modern control is of the same species as the archaeological sample, this not always being the case for seasonality studies on other types of faunal remains. However, while the need for modern control sampling is widely accepted there are still problems that can be entailed in the methods of sampling (Claassen 1991; Milner in press).

Problems of Interpretation One of the first archaeological applications of incremental growth analysis was the work of Coutts (1970) on the New Zealand cockle, Chione stutchburyi. Coutts used the work of geologists on the common British cockle, Cerastoderma edule (also known as Cardium edule) by House and Farrow (1968). This work showed that bands or rings seen on the surface of the shells, termed macro-rings, were the result of winter growth recession. Micro-bands, observed from photomicrographed cross sections of the shells were interpreted as daily bands. Coutts analysed modern samples of the New Zealand cockle and found a mean of 358 micro-bands a year. These were also interpreted as daily bands and it was shown that, provided the approximate date for the formation of macro-rings is known, the date of death of individual shellfish could be estimated by counting the number of daily growth bands between the edge of the shell and the last macro-ring (Coutts 1970).

Two of the main problems will be detailed further below; 1. Within the ecological tolerance of a species, variation in a wide range of environmental factors may produce variation in growth patterns and physical structures 2. Individual variation may be great, meaning that mean dates for population events may be inaccurate

Ecological analogy Where modern shellfish are used in seasonality studies as a growth analogy it is usually recommended that they should be taken from beaches that are as close to the archaeological sites as possible. This introduces the assumption, however, that the shellfish are growing in exactly the same manner as they were in antiquity. When deciding how to sample modern oysters for this study it was found that they are no longer so easily accessible in Denmark and now only grow in the deeper waters of the Limfjord. Added to this, the environment has changed since the Mesolithic, the temperature having fallen while eustatic and isostatic changes have occurred. This has caused the link between the North Sea and the Baltic to decrease in size, reducing salinity and tidal amplitude (Jarman et al. 1982; Rowley-Conwy 1983). Having seen in chapter 2 how much the oyster may be affected by any environmental change, it would seem likely that the oysters which may be found deep in the Limfjord today live in significantly different conditions and may respond to their environment differently compared to the Mesolithic oysters.

The interpretation that micro-banding in cockles was a daily phenomenon was used in the following years (Farrow 1971; 1972). It was later noted by Coutts (1974; 1975), however, that growth patterns did not appear to follow a logical or easily interpretable sequence and it was concluded that a great deal more work on modern specimens was needed before seasonal dating of more than a relative kind could be attempted on the cockle. This problem was resolved when it was discovered by marine biologists Richardson et al. (1979) that in fact the number of growth bands deposited in the common British cockle coincided with the number of tidal immersions, figure 3.1. This information was later used by Deith (1983) in order to interpret seasonal collections of cockles from the Mesolithic site of Morton, Fife. She too sampled modern cockles, which showed that the macro-bands formed during a period of growth recession in the colder winter months and the tidal micro-bands were shown to form from about late April to late September. For these 5 months the seasonal resolution was thought to be fairly accurate, but for the remaining 7 months of the year a blanket category of “winter collection” was used (ibid.).

This change in environment has obviously occurred in other study areas as well. An example is the site of Morton, Fife in Scotland where cockles have been examined for evidence of seasonal procurement. Here eustatic and isostatic changes have taken place and the archaeological site, which was once situated on the coast, is now 4km inland (Deith 1983). Clearly the conditions in which the archaeological specimens grew cannot be fully known. In Deith’s study two lots of modern controls are collected from two nearby estuaries, the Tay and the Eden, in order to test when growth resumed after the winter recession (Deith 1983). The samples from the Tay are taken over three years and those from the Eden over two, all from either late May or early June and the results from the two locations are in fact different. In order to identify when the cockles started to lay down the increments after the winter recession the individual tidal bands are counted back to the winter band. From this the mean and standard deviation are calculated for each sample. The variation between years and places is then analysed using t-tests. This shows that the samples differ significantly and cannot be counted as a single, homogenous group. The variation between the two sites is probably related to differing ambient environments in spite of their close proximity.

A

A

macro-bands tidal lines B

B

Figure 3.1: Section through a cockle showing thick annual lines formed in the winter and micro-lines, attributed to tidal immersions.

16

MODERN CONTROL SAMPLE AP RI L

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 34 25 26 27

MA Y

overall mean

E

*

T range of dates

50 tides from overall mean *

*

shell 1: real date of growth 3rd April *

1 shell 2: real date of growth 23rd May, harvest = June 17th *

Figure 3.2: diagram to show calendar and growth events described in the text acknowledging this range will obviously affect interpretation, see figure 3.2. If for instance 2 shells are analysed and both are found to have 50 lines between the growing edge and the last winter ring the interpretation would be that there had been 50 tides, or 25 days of growth since the winter. If the mean of April 22nd is used as the date for when growth resumed after the winter, the interpretation would be that the shells had been gathered on the 17th May. If one of the shells had actually started to grow again on the 3rd April the date of harvest would be 28th April but if the other had started to grow on the 23rd May the date of death would be 17th June. Using a mean date rather than taking account of the range can therefore mask variability in patterns of procurement.

Individual variation The importance of considering the variance in growth of shell species is argued by Claassen (1991). She suggests that any averaging or standardising growth line data is a normative approach and liable to produce erroneous results, which may influence the prediction of the season of harvest. To demonstrate the importance of considering the range of difference in growth the method of interpretation in the Morton case study will be considered further. As well as testing between the modern control samples, a t-test is performed between the modern and Mesolithic shells. In this case, the number of lines between winter rings is counted on shells that contain clear records of complete growth cycles. The test shows no significant difference between the archaeological shells and those from the Eden. Despite this, the data from the two modern sites are not treated separately, and a mean of the individual means is taken. This gives an average of 77.11 increments up to June 1st with a standard deviation of 20.19. This then establishes the mean date at which spring growth began again after the winter cessation near Morton, as April 22nd, with a standard deviation of 10 days, figure 3.2.

Conversely, if both shells 1 and 2 had actually been gathered on June 17th (and keeping their real dates of growth resumption) the number of lines will be different. Shell 2 will still have 50 tidal lines (=25 days) but shell 1 will in fact have 152 tidal lines (=76 days). In the archaeological application, using the overall mean of 22nd April, the interpretation will be that shell 1 was harvested on May 17th, but that shell 2 was harvested on 7th July. This latter date is inaccurate by 20 days but the date for shell 1 is incorrect by a whole month. Furthermore, Claassen (1991, 275) states that “because variation is present in growth records in a population, researchers who assign death times to individual shells find at least 2 seasons”.

Using the data, if the means of the two sites are treated separately the figures of 63.37 (30th April) for the Tay, and 97.71 (13th April) for the Eden are reached showing a difference of over two weeks. Although the t-test shows a match between the archaeological shells and those from Eden, the Eden date of the 13th April is not used in Deith’s study. Instead the combined mean of both sites, April 22nd, is applied directly to the archaeological data.

Past work has advanced the science of seasonality studies and it has not been my intention to criticise or condemn any studies in this section. Instead the analysis is intended to illustrate some of the current thinking on the problems which can arise in using a modern control sample as an analogy and consequently in interpretation. Innovations and ideas often arise from acknowledging that there are problems with current methods and interpretations, as seen in the history of the study of cockle seasonality.

Although the means may only differ by nine days, the overall range of dates for growth resumption for shells from both estuaries is in fact from the 3rd of April to the 23rd of May. Not 17

CHAPTER 3 taken and characteristics such as colour noted. It will be shown how these observations vary from location to location, and on a local scale between sites. These distinctions were then used in deciding how to sub-sample shells to be sectioned from the total population in order to identify any differences in the microstructure or seasonal differences.

Sampling issues The key perhaps, is that archaeological interpretation should not strive for over-precise results. It is important to identify what questions can be asked and answered with reasonable confidence given the inaccuracy of the data. No ethnographic study or modern ecological control can ever provide a precise analogy for an archaeological situation. Even when past environmental conditions have been reconstructed there are so many variables that affect shellfish growth that one cannot assess how similar these would have been to modern environments. However, a careful sampling strategy can provide some idea of variability, even though it may not be comprehensive.

The sample From each location a certain number of sites were sampled: • •

Monitoring the range and variation of growth for the species in question is therefore an important aspect of the sampling procedure. This may be achieved through the analysis of samples which:

•

Chelmsford, 10 sites (A-J) in the Rivers Croach, Roach and at the mouth of the Blackwater Southampton, 13 sites (A-M) along the Solent and up Southampton Water Truro, 20 sites (B, D, E, F, H-W) in the Helford River and Carrick Roads

See figure 3.3, (MAFF have requested that the precise locations of the sites are not specified).

a) are large samples b) have been collected from different locations with different environments c) have been collected at regular intervals over a long period of time.

The locations obviously differ in terms of environment. The Chelmsford area tends to be on average warmer than Truro and Southampton and in fact this area has been known to be a favourable part of the British coastline for oysters since the Roman period. More recently oyster spat is often grown elsewhere but re-laid here because the environmental conditions promote fast growth (Orton 1928). The sites in this area come from the mouth of the River Blackwater, and along the Rivers Crouch and Roach. The sites from the Truro area also come from rivers, the Helford and Carrick Roads, but the sites from the Southampton area come from a variety of environments along the Solent and up Southampton Water. The salinity is less likely to fluctuate here as these bodies of water are larger than the rivers of Truro and Chelmsford where freshwater may be introduced through the tributaries after rainfall. However, the tidal regime in the Solent area shows a marked increase in tidal range from west to east (2.2 m at Hurst Point and 4.1 m at Portsmouth) therefore double high waters occur in the West Solent and Southampton Water.

According to Claassen (1998) growth controls should consist of a minimum of dozens of specimens killed at monthly intervals for at least 2 full years. She demonstrates that unfortunately such controls have been poorly developed in many archaeological applications (Claassen 1998, table 9, 154).

The Modern Control Sample In this study three main areas were targeted along the coast of Britain in order to study variability in growth of the oyster, Ostrea edulis. These areas were around Truro, Southampton and Chelmsford and henceforth will be referred to as locations. From each location oysters were collected from a number of places along each estuary or stretch of coast and these will be referred to as sites. A sample of known age was also obtained from a shellfish farm in Whitstable.

It was also possible to collect oysters of known age to test the identification of annual lines, before any interpretation of age and seasonality was made. This has never been attempted by archaeologists investigating the skeletal growth of molluscs because it can be problematic obtaining such specimens. Ostrea edulis, however, is farmed and Seasalter Shellfish Ltd. Whitstable provided 2 batches of oysters of known age. Unfortunately the Ostrea edulis beds had been destroyed in a storm in the winter of 1995-1996 but some oysters which had not been swept away were collected from the sea bed on 19th April 1996. These were labelled batch 1 and were thought to be 4 years old (Martin Convery pers. comm. 1996). Another batch was sent on the 2nd of May 1996, aged 2 years old.

The oysters were collected by the local Public Health Authorities for microbacterial examination for the Ministry of Agriculture, Fisheries and Food (MAFF) in accordance with EC guidelines. The sample used in this study was gathered on a monthly basis from December 1995 until March 1997 (unfortunately no longer due to Ph.D. time restrictions). Although this only represents 16 months, it covers 2 spring periods when annual line formation occurs. In addition it was possible to observe the past years of growth within the incremental structure to see how annual growth might vary from year to year, although ideally it would have been better to collect the sample for a longer period. The total sample size was approximately 2750 oysters, that is about 170 oysters per month. Not all of these were thin sectioned but all were catalogued. Various measurements were

18

MODERN CONTROL SAMPLE

River Blackwater Chelmsford

River Crouch River Roach

4 miles

Southampton 4 miles

Truro

Carrick Roads

Southampton Water

The Solent

Helford River 4 miles

Isle of Wight

Figure 3.3: maps to show the locations where the modern control samples of oysters were collected from. Southampton Truro Chelmsford

The oysters from Southampton were collected from December 1995 to March 1997, those from Truro from March 1996 to April 1997, and Chelmsford from March 1996 to March 1997. In January 1996 no oysters were collected from Southampton due to bad weather conditions. Also in October 1996 and February 1997 no oysters were sent from Southampton, and in January and February 1997 no oysters were sent from Truro. See tables 3.1, 3.2, 3.3 and 3.4 for the numbers of oysters collected and dates of collection for each batch.

December 1995

75

January 1996 February

85

March

106

48

58

April

92

77

91

May

75

65

94

June

73

87

69

July

75

32

44

August

54

56

56

September

62

October

Table 3.1: number of oysters received from each location for each month. In some months oysters were not collected due to bad weather conditions.

76

66

72

89 55

November

73

68

December

67

48

January 1997

86

February March

19

79 103 66

107

67

44

CHAPTER 3

Batch No.

1 2 3 4 5 6 7 8 9 10 11 12 13

Site A

B

C

D

E

F

G

H

I

J

2-Apr-96 13-Mar-96 13-Mar-96 18-Mar-96 18-Mar-96 19-Mar-96 19-Mar-96 19-Mar-96 10-Apr-96 10-Apr-96 15-Apr-96 15-Apr-96 15-Apr-96 15-Apr-96 15-Apr-96 13-May-96

5-Jun-96

5-Jun-96

17-Jul-96 10-Jul-96 10-Jul-96 15-Jul-96 15-Jul-96

17-Jun-96

15-Jul-96

30-Aug-96 7-Aug-96 7-Aug-96

15-Jul-96 14-Aug-96

17-Sep-96 9-Oct-96

5-Jul-96

5-Jul-96

6-Aug-96 6-Aug-96

10-Sep-96 11-Sep-96 11-Sep-96 11-Sep-96

2-Oct-96

2-Oct-96

9-Oct-96 14-Oct-96 14-Oct-96 14-Oct-96 17-Oct-96 17-Oct-96

21-Nov-96

22-Nov22-Nov- 11-Nov- 11-Nov-96 96 96 96 13-Dec-96 5-Dec-96 5-Dec-96 9-Dec-96 9-Dec-96 6-Jan-97

9-Apr-96

13-May-96 13-May-96 13-May-96 22-Apr-96 22-Apr-96

20-Jun-96 26-Jun-96 26-Jun-96 12-Jun-96 12-Jun-96 17-Jun-96

18-Oct-96 25-Oct-96 25-Oct-96

9-Apr-96

14-Nov-96 14-Nov-96 10-Dec-96 16-Dec-96 16-Dec-96

6-Jan-97 22-Jan-97 22-Jan-97 22-Jan-97 22-Jan-97 22-Jan-97 15-Jan-97 15-Jan-97

7-Feb-97 3-Feb-97 3-Feb-97 5-Feb-97

5-Feb-97

5-Mar-97

7-Mar-97

7-Mar-97

27-Feb-97 27-Feb-97 7-Mar-97

7-Mar-97

Table 3.2: Dates and batch numbers for each site at Chelmsford. Batch No. Date of Collection 1 22nd March 96 (Carrick Roads) 23rd March 96 (R.Helford) 2 22nd April 96 (Carrick Roads) 23rd April 96 (R.Helford) 3 22nd May 96 4 2nd June 96 5 29th July 96 6 19th August 96 7 9th September 96 8 1st October 96 9 18th November 96 10 2nd December 96 11 17th March 97

The oysters when gathered had been bagged and labelled according to site and the date of collection. On receipt of the oysters any remaining flesh was removed and later incinerated and then the shells were re-bagged in hessian and labelled. They were boiled for over an hour to thoroughly kill any bacteria and finally rinsed by hand before being laid out on drying racks. Once dried, each valve was catalogued. They were coded according to location, batch number, site, sample number and valve e.g. C.1.A.10.L. • • • •

Table 3.3: Batch numbers relating to the date of collection for sites around Truro Batch No. 1 2 3 4 5 6 7 8 9 10 11 12 13

•

Date of Collection 4th December 95 13th February 96 4th March 96 25th April 96 28th May 96 24th June 96 28th July 96 19th August 96 30th September 96 25th November 96 16th December 96 20th January 97 24th March 97

The first letter is coded as to the location, C=Chelmsford, T=Truro, S=Southampton, and W=Whitstable The following number refers to the batch, or month The next letter indicates the site. The following number simply refers to the sample number. The final letter is added once the shell has been sectioned indicating whether the section was taken from the right or the left.

For instance, the first batch (1) collected from site A (A), Chelmsford (C) had a total of 10 valves which were numbered 1-10. The above example, C.1.A.10.L is the last valve numbered in this batch and once the shell had been sectioned the left (L) half of the hinge was made into a thin section. Each valve was labelled with its code using a waterproof marker. They were then catalogued. Firstly a series of measurements were made to a tenth of a millimetre using electronic callipers. Richardson et al. (1993) used measurements to compare the age of the oyster to shell length and this approach was used here.

Table 3.4: Batch numbers relating to the date of collection for sites around Southampton

20

MODERN CONTROL SAMPLE

E

A

encountered, in that the shells often grew on a skew. The shell length measurements were therefore taken from the tip of the hinge along roughly the greatest length. The hinge in these circumstances had to be measured at right angles to the growing edge, this line also being used as the plane along which the hinge was sectioned. The measurements from the nacreous shell length were used and a bivariate analysis was made to see if there was any difference in the rate of hinge growth to nacreous shell growth.

C

F

It became clear, even after a couple of months of receiving the oysters, that there were clear differences between the various locations as well as between sites. By plotting the hinge length to nacreous shell length a rough visual guide could be obtained showing the difference in average sizes of the shells. Figure 3.5 shows average size of shell between Truro, Southampton and Chelmsford. Whitstable is not included here because there were only 2 batches, and hence only 2 points. Each point is the average hinge length and nacreous shell length for each site every month. This graph does not take into account the different ages of the shells and obviously a shell of 5 years is going to be larger than one of 2 years, but this is in general averaged out and the graph is only intended to be a rough guide of oyster sizes.

nacreous shell

D prismatic layers

B

Figure 3.4: Diagram to show how measurements were taken for each valve. A-B is the measurement from the hinge tip to rim axis, C-D the measurement of hinge tip to nacreous shell growing edge, and E-F the measurement along the growing plane of the hinge.

It can be seen that the oysters from Chelmsford are on average larger than those from Southampton and Truro. Whereas those from Southampton have a fairly linear relationship between hinge length and length of nacreous shell, the points plotted for Truro and Chelmsford are more spread out. It can be seen that the points from the Truro oysters tend to fall to the left of the Southampton distribution indicating smaller hinges in relation to the length of the shell. The distribution of points from the Chelmsford shells on the other hand show average hinge lengths to the right of the Southampton shells indicating slightly larger hinge lengths to shell length. It is quite clear that the oysters from the three locations grow in distinct ways. This analysis of shell measurements therefore shows that oysters from these three locations could not be grouped into one set.

The length from the hinge tip to rim axis was measured, shown in figure 3.4 as line A-B, but it was found when attempting this that several problems arose. Firstly the delicate prismatic layers tended to be broken and there was no way of knowing whether some of these laminae had snapped off or whether they were intact. The nacreous layer was therefore measured as this was more robust and was not broken as often, line C-D on figure 3.4. As the archaeological valve is often broken, and certainly the prismatic layer is never preserved, the hinge was also measured, line E-F. It was found, perhaps not suprisingly, that the hinge generally grew proportionately to the shell length. A second problem was however

average height of nacreous shell (mm)

100 90 80 70 60 50

Truro Chelmsford Southampton

40 30 4

6

8

10 12 average hinge height (mm)

21

14

16

Figure 3.5: Averages of hinge length to nacreous shell length for the locations of Chelmsford, Truro and Southampton for every site and each batch.

CHAPTER 3 A further assessment of sites within these three locations indicates that there are significant differences between oysters from sites that occur in close proximity. The results of measuring oysters for these sites will be presented in further graphs. The colour of the exterior of the shell was noted. The right valves only tended to be brown with the odd streak of purple but there were significant differences in shell colour for the left valves, probably due to differences in minerals present in the water. These differences in colour will also be compared.

Theoretically the sea temperature should be more stable because water is denser than air and should take longer to heat up and cool down. In fact the sea temperatures in general tended to mirror air temperatures, although brief fluctuations are not usually registered. The readings given are of course only averages for each month, and the sea temperatures are surface temperatures. The temperatures will be lower and more constant at the actual depths of the oyster beds and the same can be said for the salinity readings. Despite these restrictions and the fact that the other major factor affecting growth, namely food, has not been monitored, the temperature and salinity charts do give a good comparison of the differences in ambient environment for the various locations.

Any other observations were also noted. At many of the sites the shells exhibited evidence for the presence of predators and parasites. Holes in the shell were sometimes seen. As described in chapter 2 these may have been caused by drills, parasitic snails, sponges and bristle worms. Calcified worm casts and mucous tubes of mud and sand were common and small barnacles, sponge, sea weed, squirts and hydroids were also noted. It is very difficult to quantify such observations and therefore the types of epifauna and a rough picture of their relative abundance will be given by describing coverage as sparse, medium or total.

Southampton

Finally it was considered important to understand something of the environmental conditions at the various locations and sites. It was shown in chapter 2 that certain changes in salinity and temperature affect the growth of the oyster. It cannot tolerate salinities below 23‰ and this figure needs to be higher for larvae to survive. Under higher temperatures the filtration rate of the oyster will increase, supplying more food, and providing more oxygen. Spawning tends to occur at about 15-16°C but higher temperatures are needed for successful incubation and growth. Extremes in either salinity or temperature however, may cause major trauma and brief cessation of growth.

Two groups of scatters stand out in this plot. The sites of A, E and I (marked with crosses) clearly have a small average size compared to the other sites. Those sites represented by the circles; D, F, G, L and M, appear at the top end of the scale and are on average larger shells. These differences between groups are shown more clearly in figure 3.7. Oysters from H, J, K, B and C (triangles) are scattered in the middle of the latter two groups. The points from J do tend to have larger measurements. Those from B and C appear to have slightly larger shell lengths to hinge lengths.

The average measurements of hinge against nacreous shell length for sites in the Southampton area can be seen in figure 3.6. The graph shows the average measurements for each location each month. These sites have been split into four groups.

These groupings do in fact correlate with the location around the coast. D, F, G, L and M (hereafter Group 1) are noted as being larger shells and are all located to the west of the study area. They are actually situated near the mouth of a sewage

Figure 3.6: graph to show the average measurements of hinge length (in mm) against nacreous shell length (in mm) for each site each month within the Southampton area.

average height of nacreous shell (mm)

Monthly temperature and salinity readings were obtained for the four locations from Maldon District Council, Falmouth and Truro Port Health Authority, New Forest District Council and the Harbour Office at Whitstable, for the periods 85 when the oysters were being collected. For the 80 Chelmsford sites both the air and sea temperatures 75 were compared to see how much these differed 70 because usually when past environments are described an estimation of average 65 air temperatures are given rather than sea 60 temperatures.

D F G L M J H K B C I E A

55 50 45 5

7

9 average height of hinge (mm)

22

11

13

MODERN CONTROL SAMPLE

75 average nacreous shell height (mm)

Figure 3.7: Average measurements of shell height and hinge height (in mm) for group 1 (D,F,G,L,M) and group 2 (A,E,I)

50

A,E,I D,F,G,L,M

25 5

6

7

8

9

10

11

12

13

average hinge height (mm)

sea squirts. Further along the coast the oysters from Group 4 were “cleaner” with little to medium coverage of mainly mud tubes, barnacles and weed.

outlet which might possibly account for their larger size, the sewage making the water more nutritious which would in turn promote the growth of plankton and micro-organisms. A, E and I (Group 2), those noted as being smaller in size are located at the mouth of the Solent. H, J and K (Group 3) are located in the Solent. J appears to have oysters which are slightly larger than H and K but it certainly does not fall into Group 2 where the oysters are much smaller. B and C (Group 4) are located further to the east, down the coast.

Temperature and salinity readings for the sites M and F were obtained from New Forest District Council for the period in which the shells were collected. Unfortunately there are a few gaps in the data when readings could not be taken. Figure 3.8 shows that the maximum temperatures appear to be around 20°C although they may reach a little higher in August. The winter lows are just below 5°C.

These differences between groups are also reflected to a great extent in terms of colouring of the lower valves (for full descriptions see Milner 1998). The colouring of lower valves in Group 1 are very distinct, the shells tending to be mostly green. Those from Group 3 have more orange, blue and brown on their shells, in fact these are the only sites which do exhibit blue streaks. Those shells from H and K are especially similar. J shells are predominantly orange and brown with no yellows or purples. The colouring of the E and I shells are similar, about half of them being green with some orange, brown, yellow, white, pink and purple. Those from A have the same colours but there tends to be more orange. This is fairly similar to B and to some extent C although the shells from these sites can be seen to have a greater proportion of white and brown on their shells.

The salinity readings vary greatly over this period and at F they reach a high of 38 ‰ in the winter of 1996, figure 3.9. It is interesting to note that these sites are relatively close together and yet the readings are different, presumably due to varying fluctuations of freshwater into the sea from nearby rivers and streams.

Temperature (degrees C)

25

The shells collected from the sites of Group 1 tended to provide a habitat for a variety of predators and parasites and the coverage of the surface of the shell was medium to full. A lot of the shells were covered in different seaweeds and sea squirts and there was often various types of sponge, worm burrows, some barnacles and holes, some of them fairly large, presumably made by various species of worms, drills and sponges. Group 2 also had a high coverage of epifauna on the valves. These were often mainly barnacles and worm burrows at I, but at A and E there tended to be more mud tubes from the bristle worm, weed, seasquirts and holes. Group 3 tended to have a medium to high coverage, mainly made up of barnacles and worm burrows, some mud tubes, seaweed and

20

M F

15 10 5

De c9 Ja 5 nFe 96 bM 96 ar -9 Ap 6 r-9 M 6 ay Ju 96 n9 Ju 6 l-9 Au 6 gSe 9 6 p9 O 6 ct -9 N 6 ov D 96 ec Ja 96 nFe 97 bM 97 ar -9 Ap 7 r-9 7

0

Figure 3.8: Graph to show temperature readings taken at the sites of M and F, Southampton. Missing months due to equipment failure. Data kindly supplied by Environmental Health Services, New Forest District Council.

23

CHAPTER 3 on the whole, larger than those from the slightly more exposed locations of I and J. 39 salinity gm/1 NaCl x 1000

38

In comparison with the Southampton sites the shells are all fairly similar in terms of colour. Those from the River Roach however, do exhibit some green and more yellow colouring with a little less white, than those from River Blackwater. Sites B and C are very similar because they are located so near to each other. Sites D and E exhibit a greater degree of blues, greens and orange, with less white, yellow and pinks. These are very different to the other sites.

37 36 35 34 33 32

M F

31

The shells from the Chelmsford area were by far the cleanest with little epifauna. In addition to the oysters from Chelmsford being larger than those from Truro and Southampton the barnacles on the valves were also seen to be much bigger than those from the other locations. The shells from the Blackwater tended to have some sand and mud tubes, formed by the bristle worm, and the occasional hole or barnacle together with a little weed. The shells from the River Croach were much the same although at the site of Althorne there appeared to be quite a high number of valves which either had other species of shells growing on them, especially over the hinge area, or else this was depressed and patterned as if a cockle or other shell had once grown there. All the shells from the River Roach had very little coverage with the occasional piece of seaweed, and the odd barnacle or mud tube.

D ec Ja 95 nFe 96 bM 96 ar Ap 96 r-9 M 6 ay Ju 96 n9 Ju 6 l-9 Au 6 gSe 96 pO 96 ct N 96 ov -9 D 6 ec Ja 96 nFe 97 bM 97 ar Ap 97 r-9 7

30 29

Figure 3.9: Salinity readings for M and F, Southampton. Missing months due to equipment failure. Data kindly supplied by Environmental Health Services, New Forest District Council.

Chelmsford The measurements for oysters from the Chelmsford sites have been plotted in figure 3.10. Again each point plotted is the average nacreous shell length and hinge length for each site every month. It can be seen that the distributions of measurements are different for each site. Those from the mouth of the River Blackwater (A, I and J) are represented by a diamond, those from the River Croach (B,C, D and E) are represented by a square and those from the River Roach (F, G and H) are represented by a circle.

In terms of environmental conditions figures 3.11 and 3.12 show that temperature and salinity readings for various areas vary slightly according to location. Although the oysters were only collected from these sites between March 1996 and March 1997 a whole picture of 2 years has been included as an indication of how changes may occur from year to year.

Those at the mouth of the River Croach (B and C) are clustered at the centre of the distribution. Those further upriver (D and E) however, have a smaller ratio of shell length to hinge length. The measurements of oysters from the River Roach tend to be smaller in size compared to the overall distribution. Those oysters from the mouth of the River Blackwater were in general large although those from A were, 95

Figure 3.10: Graph to show the average measurements of hinge length against nacreous shell length for each site each month within the Chelmsford area.

90

nacreous shell length (mm)

85 80

A

75

B

70

D

C E F

65

G 60

H I

55

J

50 7

9

11

13

15

17

hinge length (mms)

24

19

21

MODERN CONTROL SAMPLE Site J

It can be seen from the comparison of air and sea temperatures between these three sites that sea temperatures tend to read the same as air temperatures although brief fluctuations do not tend to register. A slight difference in years may be seen. In 1997 temperatures were on average higher but the salinity tended to fluctuate more. These graphs also show slight differences in temperature between the sites. Site J, which is located further out to sea, exhibits greater fluctuations in air temperature, going from -2°C in the winter months to 27°C in June 1997. The sea temperatures are not quite so extreme. Those more sheltered locations of A and the River Croach, have less dramatic fluctuations.

Air Sea

25 20 15 10 5

M 96 ar -9 Ap 6 rM 96 ay Ju 96 n9 Ju 6 lAu 96 gS 96 ep -9 O 6 ct N 96 ov D 96 ec -9 Ja 6 nFe 97 bM 97 ar A 97 pr M 97 ay Ju 97 n9 Ju 7 lAu 97 gSe 97 p9 O 7 ct N 97 ov De 97 c9 Ja 7 nFe 98 b98

0 -5

Fe b

Temperature (degrees centigrade)

30

-10

The salinity readings are also similar for these two sites with E, being upriver in the Crouch, generally displaying lower readings. River locations tend to produce lower readings and greater fluctuations as ratios of salinity change due to the addition of freshwater from tributaries. In February 1998 the salinity appears to fall to very low levels which the oyster theoretically should not be able to tolerate and they therefore must have been very brief events.

30 Air Sea

25 20 15 10 5 0

Truro

Fe bM 96 ar -9 Ap 6 rM 96 ay Ju 96 n9 Ju 6 lAu 96 gSe 96 p9 O 6 ct N 96 ov De 96 cJa 96 nFe 97 bM 97 ar -9 Ap 7 rM 97 ay Ju 97 n9 Ju 7 lAu 97 gSe 97 p9 O 7 ct N 97 ov D 97 ec -9 Ja 7 nFe 98 b98

Temperature (degrees centigrade)

River Crouch

The measurements for the oysters from sites at Truro have been re-plotted on figure 3.13. A couple of sites have been excluded from the analysis as the sample sizes were very small and batches had been sent on fewer occasions than the other sites. The 13 sites chosen for this analysis from Carrick Roads have been split into two different groups. Those further upriver, F, H, R, J, Q and S are represented by diamonds. Those nearer the mouth of the river, N, I, M, K, P, T and O are represented by squares. Those from the River Helford (U, V and W) are represented by circles.

25 Air Sea

20 15 10 5

Even though these sites have been separated according to location within Carrick Roads no real difference in the size of oysters could be detected at Truro. The range of sizes is spread out for all the sites in Carrick Roads and those from the River Helford are centred in this distribution. This is perhaps not suprising as all the sites are in much closer proximity to each other than at the other locations and therefore the ambient environment is likely to be fairly similar at each site.

0 Fe bM 96 ar -9 Ap 6 rM 96 ay Ju 9 6 n9 Ju 6 lAu 96 gSe 96 p9 O 6 ct N 96 ov D 96 ec -9 Ja 6 nFe 97 bM 97 ar -9 Ap 7 rM 97 ay Ju 9 7 n9 Ju 7 lAu 97 gSe 97 p9 O 7 ct N 97 ov D 97 ec Ja 97 nFe 98 b98

Temperature (degrees centigrade)

Site A

Figure 3.11: Graphs to show variations between air and sea temperatures for the sites of site A at the mouth of the Blackwater, J which is further out to sea and the River Croach. Data kindly supplied by Maldon District Council.

salinity gm/1 NaCl x1000

34

There is not a great deal of difference in colouring of the left valves from this location, although subtle differences linked to location have been observed. J, Q and S do have some white colouring, more green and less orange than F, H and R which are slightly further upriver. Those further downstream do not differ greatly from these. A large proportion of shells display green and orange colourings although with the exception of P there are less valves exhibiting the colour brown. The shells from O are also slightly different in that only the three main colours green, brown and orange were noted. Those shells from the River Helford, figure 3.3, again are fairly similar, with a high proportion of orange and green, and some brown, purple and white but no other colours such as pink and yellow.

32 30 28 26 24 22

A J E

Fe bM 96 ar Ap 96 r M -96 ay Ju 96 n9 Ju 6 lAu 96 gSe 96 pO 96 ct No 96 v D -96 ec Ja 96 nFe 97 bM 97 ar Ap 97 r M -97 ay Ju 97 n9 Ju 7 lAu 97 gSe 97 pO 97 ct N -97 ov D 97 ec Ja 97 nFe 98 b98

20

Figure 3.12: Graph to show variations in salinity between the sites of A, J and E. Data kindly supplied by Maldon District Council. 25

CHAPTER 3 73 F

H

I

J

K

O

67

P

R

65

S

T

U

V

W

M

N

Q

71

nacreous shell length (mm)

69

63

Figure 3.13: Graph to show the hinge length plotted against the length of the nacreous shell for sites in the River Helford and Carrick Roads.

61 59 57 55 5

6

7

8

9

10

11

Sea Temperature (Degrees C)

hinge length (mm)

As the sites are all in close proximity the shells tended to have the same epifauna with medium to full coverage of the shell. Worms and barnacles tended to predominate with seaweed and sea squirts, sponge, and holes. No major differences were observed between these sites.

18

15

12

The similarities exhibited in terms of size and characteristics are not suprising when the temperature readings for the various sites are compared. Figure 3.14 gives the sea temperatures over two years for three sites; O near the mouth of Carrick Roads, R further upriver and the River Helford.

9 O R Helford

6

Jan-98

Feb-98

Dec-97

Oct-97

Nov-97

Sep-97

Jul-97

Aug-97

Jun-97

Apr-97

May-97

Mar-97

Jan-97

Feb-97

Dec-96

Oct-96

Nov-96

Sep-96

Jul-96

Aug-96

Jun-96

Apr-96

May-96

Mar-96

Jan-96

Feb-96

3

The temperatures for the three areas are fairly similar and in 1997 the temperature at the Carrick Road sites is on average slightly higher in the summer than it was in 1996, although it is several degrees lower in the River Helford. The salinity readings in figure 3.15, however, vary dramatically and at times the readings fall way below the supposed tolerance levels of the oyster for site R. Even so, referring back to average oyster size on figure 3.13, the size of these oysters are not abnormal. The location far upriver probably results in the occasional influx of freshwater, especially in autumn/early winter at times of high rainfall. These will however be brief events and obviously do not affect growth dramatically. The salinity readings are also sometimes very high going over 40‰ which may be a reason why the oysters from Truro are relatively small in size.

Figure 3.14: Graph to show the temperature readings for 2 sites on the River Fal, O and R, and the River Helford. Readings were not taken every month, hence the gaps in the lines. Data kindly supplied by Falmouth and Truro Port Health Authority.

35 30 25

Jan-98

Whitstable can not really be analysed in the same manner as the other locations because this site was sampled for different reasons, the shells being collected for the purpose of identifying an annual line. Only two batches were received from March and April in 1996, and the latter batch was not analysed in detail because the oysters were so small, only two years old. For the purpose of comparing locations the average hinge length was 11.45mms and the average nacreous shell layer length was 62.91mms. On figure 3.5 this would fall within the Chelmsford size scatter, the larger sized valves.

Feb-98

Dec-97

Oct-97

Nov-97

Whitstable Sep-97

Aug-97

Jul-97

May-97

Apr-97

Mar-97

Jan-97

Feb-97

Dec-96

Oct-96

Nov-96

Sep-96

Jul-96

Aug-96

Jun-96

May-96

Apr-96

Mar-96

10

Jan-96

15

Jun-97

O R Helford

20

Feb-96

Salinity gm/1 NaCl x100

40

Figure 3.15: Graph to show the salinity readings for 2 sites on the River Fal, O and R, and the River Helford. Those readings at 40‰ were maximum instrument readings but in fact the values were higher. The gaps represent months when readings were not taken. Data kindly supplied by Falmouth and Truro Port Health Authority. 26

MODERN CONTROL SAMPLE The colouring of the external side of the left valves tends to be fairly evenly spread between greens, pinks, white and yellows. The valves tended to be fairly clean with only a few barnacles, worms, and seaweed. The average air temperature for mid March 1996 was 5°C and for mid April 1996, 12°C (Data from the Whitstable Harbour Office).

almost impossible to section. Thirdly, this total includes left and right valves many of which can be paired. A number of shells of approximately known age had been collected from Whitstable in order to see whether “annual lines” identified by Richardson et al. (1993) could be correlated with age. If they could, it was then necessary to determine their characteristics in order to distinguish them from other disturbance lines. Experiments were also carried out on these shells to see which valve, either upper or lower, was the better to section. This was the first location to be subsampled and 10 left valves and 32 right valves were used from Batch 1. The samples from Batch 2 were too small, aged 2 years only.

Summary of differences It has been shown that the oysters from Whitstable, Chelmsford, Southampton and Truro vary considerably when the average sizes, colour and epifauna are compared. Those oysters from Chelmsford tend to be fairly large with “clean” shells; very few worms, sponges or barnacles settle on them. They are pale in colour with streaks of pink and purple running across them. Those from Whitstable are similar to an extent although their colouring includes green, and although they are fairly large they do not fall into quite the same scale as those from Chelmsford. The oysters from the south coast locations of Southampton and Truro are usually smaller, their colouring tends towards greens, browns and oranges, and their exteriors are apt to be covered in epifauna.

Almost 100 shells were used in other methodological experiments and various techniques of impregnation, cutting and bonding were tried and tested. Once the method of manufacturing the sections was regarded satisfactory, shells from Whitstable, site F of Southampton and site J of Chelmsford were all used to test the positioning of the cut. Thin sections were made from the right and left hand sides of the hinge (rather than choosing just the one side) to see if the structure and readings were reproduced in both halves after the shell had been ground away a little during the thin sectioning process. In some cases another section was made from the same block which is sectioned after the sample had been bonded to the slide (see following chapter). This then gives a section, termed here a “re-make”, the cut of which will be offcentre.

Within these locations differences may be observed between the sites themselves. These differences between sites and locations can be explored, to a certain extent, in terms of the ambient environments. There are, however, so many variables affecting growth the exact reasons for differences will never be known without conducting detailed laboratory experiments controlling and altering certain variables. When these three locations are compared in terms of salinity and sea temperature it can be seen that they vary significantly. Chelmsford is especially different to Southampton and Truro. At the latter two locations average temperatures are lower and salinity appears to fluctuate more, as well as being fairly high. At Chelmsford the temperatures tend to be a couple of degrees higher in the summer and the salinity stays fairly constant. These conditions will also relate to food availability as in favourable circumstances plankton flourishes but there are other factors such as the tidal amplitude that play a role. The more favourable conditions of Chelmsford are reflected in the observations made on size, if not also the external characteristics.

Once these methodological issues had been addressed it was necessary to decide how the other shells would be subsampled in order to investigate the differences between sites and locations. As a rough guide it was decided that approximately 100 shells were to be selected from each location and from several of the sites within each location. There were two main objectives. Firstly it was imperative to identify the time at which the annual line formed, the variability and range. This would involve selecting shells that had been collected in the spring months. Secondly, in order to understand the yearly cycle of growth and to identify when other lines may appear and when growth slows down there was the need to sample shells from every month. For the Southampton sites a selection of shells was taken from each group in order to analyse variability between them. Several sites were also chosen from each group in order to see whether there would be any difference between these. Shells from D and E were specifically selected for analysing the spring months. It should be noted that the shells from D were comparatively large and those from E were in a group which was on average small in size. In these cases usually about 3 or 4 shells with good hinges were chosen for each month. For all the other chosen sites 1 or 2 shells were taken from each of the 13 months of collection. Although this gave a very small sample per site it was thought that sites within groups would be comparable. Table 3.5 gives exact numbers of each sample for each site and the time span covered.

It is clear that these locations and sites have different environments that are reflected in the oyster’s characteristics. Variability in growth of the oysters may therefore be examined in detail by carefully sub-sampling the total population and thin sectioning.

Sub-Sampling Although it may seem like a good idea to thin section the whole control sample there are several restrictions. Firstly it totals 5504 valves which would have taken far more time and resources than were available for this project. Secondly many of the valves were actually fairly useless in that the hinges were damaged or that they had grown on such a skew as to be 27

CHAPTER 3

Site Group 1 F L D

Number 96 13 13

The shells that were sub-sampled from Chelmsford were selected from the three rivers. Sites J and A were sampled from the mouth of the Blackwater. The comparison of environmental conditions from these sites had shown that there were greater fluctuations for the more exposed location of J. At both these sites more oysters were sampled from spring collection dates, although the sample from A included oysters collected in every month. E and D were sampled from upriver in the Crouch. A shell was sampled from every monthly batch for E and several shells were selected from the spring months for D. Finally, to compare these sites with the River Roach several samples were taken for every month for the site of H. Table 3.7 gives these sub-sampling details.

Selection all year, R + L, remakes all year February-July

Group 2 E I

16 13

March-June all year

Group 3 H K J

13 19 14

all year all year all year

Group 4 B C

12 13 222

all year all year

Summary It was shown at the beginning of this chapter that modern control samples could not simply be taken from a location near to the archaeological site in question and then used as a direct analogy when interpreting the seasonality of the archaeological specimens. Instead the variability of growth and the range in periodicity of certain events should be fully researched. In order to carry this out, oysters of known date of collection and in some cases known age were analysed from the locations of Chelmsford, Southampton, Truro and Whitstable. It was shown that substantial differences in oyster size and characteristics and ambient environment existed not only between these locations but between the various sites within them. This data was used carefully to sub-sample a total of 484 shells for thin sectioning in order to test whether these differences were evident in the microstructure. It was also imperative to ascertain the timing of annual line formation and to understand growth patterns throughout the year in order to successfully interpret the archaeological sample.

Table 3.5: This table shows the number of samples taken for each site at Southampton and the months of the year the shells were selected from. The shells from Truro did not appear to differ significantly from site to site but a sub-sample to compare shells from the River Helford and Carrick Roads was made, as well as from 2 sites in Carrick Roads. The selection of shells from the River Helford was taken in the spring and summer months in order to establish the timing of annual line formation. The two sites in Carrick Roads, which were chosen, were R and O. To reiterate, R is located upriver and the salinity at this site fluctuated quite dramatically at certain times of the year. Site O on the other hand was nearer the mouth of Carrick Roads and displayed a minor variation in colour. For these two sites 3 or 4 shells were selected from each month in order to investigate growth all year round. Table 3.6 shows these subsampling details.

Site Helford R O

Number 27 47 33 107

Selection March, April, May, June, October all year all year

Table 3.6: Table to show the number of samples selected for Truro and the months of the year the samples were taken from. Site A J E D H

Number 36 35 12 10 20 113

Selection mostly all year but a couple more in the spring months spring months, L and R sides, remakes all year spring months all year

Table 3.7: Table to show the number of shells selected for each site at Chelmsford and the months in which they were selected. 28

CHAPTER 4

Methodology

There are several methods which may be employed to examine the molluscan skeletal record and the technique chosen ultimately depends on the species under examination, the questions being asked and of course the time, finances and equipment available. Early studies of shell structure at the beginning of this century were based on the examination of petrographic thin sections. These however, required a large investment of time and labour and the shells tended to split along the growth surfaces or boundaries. There was therefore a shift in approach to taking an acetate peel from a sectioned and etched surface (Clark II 1980). Archaeologists have tended to use this method as it usually produces good results, is cheap and is not time consuming. Other means which may be employed include differential staining, oxygen isotope analysis, scanning electron microscopy, and thin sectioning. In this research a method had to be used which was going to enable some interpretation of seasonality to be made. This required examining an area of the shell which had grown incrementally and was complete with growing edge, the area of the shell where material is deposited periodically. It therefore seemed shrewd to examine the microstructure of the hinge area. Oysters from archaeological deposits are often broken or very fragmentary but the hinge is more solid and tends to remain intact. What is more, it has been shown that annual lines are the most clear in this region for both American and European oysters (Custer and Doms 1990; Kent 1988; Richardson et al. 1993). As the hinge of Ostrea edulis is often only millimetres in length, a method was required that could physically be employed and that would enable the structure to be examined in high resolution. Firstly this chapter will describe the standard methods used and show how they have been applied in archaeological studies. An examination will then be made as to whether or not the different approaches could be applied to Ostrea edulis, and experimentation with their application will be outlined. Finally, it is shown that thin sectioning was chosen as the most suitable method for this study and a detailed description is given of how it was tailored for the oyster, as well as outlining the experiments and problems encountered along the way.

CHAPTER 4 changes in the shell structure. This tends to occur on sites which are badly drained (Deith 1985).

Methodologies

Archaeological analysis has been performed on cockles, Cerastoderma edule, from the Mesolithic site of Morton, Fife (Deith 1986), on hard clams, Mercenaria spp., from the south-east U.S.A. (Quitmeyer et al. 1997) and on the butter clam, Saxidomus giganteus, from Alaska (Fitzhugh 1995). Quitmeyer et al. (1997) and Fitzhugh (1995) both used this analysis for linking morphological features of the clam to seasonal fluctuations in the isotope ratios, correlating water temperatures with seasons and observations in the translucent and opaque shell growth increments. Deith also uses a multifaceted approach linking growth line analysis from acetate peels, to oxygen and carbon isotope ratios in order to provide information as to the seasonal exploitation of cockles (Deith 1986).

Differential Staining Staining methods were used by Kent (1988) in order to enhance differential staining of the ligostracum of Crassostrea virginica. Because the seasonal bands on the hinge of the oyster are produced by an alteration of calciumrich and conchiolin rich layers, double staining was used to help delimit these bands. Hematoxyin was used to stain the calcium-rich layers and eosin the conchiolin ones. The oysters were first etched in sodium hypochlorite which rapidly attacks the conchiolin, and then stained with hematoxyin, and finally counter-stained with eosin. The hematoxyin stains the calcium a violet colour and the eosin turns the conchiolin pink. Contrast can be heightened by applying light-weight mineral oil. The hinges can then be viewed under a dissecting microscope with a diffuse light.

Scanning Electron Microscopy (S.E.M.) Scanning Electron Microscopy is not often used in the study of archaeological molluscan seasonality, probably because it is so expensive. It may be employed if a higher magnification is required to examine the microgrowth increments, but it is more likely to be used for examining shell structural changes (Lutz and Rhoads 1980). S.E.M. techniques may also be applied for observing the organic matrix of molluscan shell where light microscopy of thin sections cannot reach the magnification required to distinguish most matrix elements (Clark II 1980).

There are however problems with this approach. Badly eroded or discoloured valves are difficult to stain, stained hinges are prone to fade, and they are bulky and difficult to store. Kent also used the acetate peel method and claimed that this was undeniably easier to learn and interpret (Kent 1988). Custer and Doms (1990) used Kents pioneering work on Crassostrea virginica to interpret seasonality of oysters from shell middens in the Delmarva Peninsula, North America, but they only used the acetate peel method and did not undertake differential staining. Coutts and Jones (1974) also attempted a staining method used on the echinoid, Evechinus chloroticus, but found this method hard to apply so employed medical Xrays instead to delimit the structure into black and white bands.

In order to prepare the shells for examination the valves can be fractured. They should be thoroughly dried prior to fractioning and then broken along the desired axis. It is important to break the shell edge away from any shell surface that is of interest. The fractured shell fragment may then be mounted on a standard S.E.M. stub and silver paint or graphite solutions used as mounting media to ensure that there is electrical conductivity between the specimen and the stub. Clean compressed air should be used to remove all contaminants from the surface of the specimen and finally it should be coated, under vacuum, with gold-palladium or a combination of gold and carbon (Kennish et al. 1980).

Oxygen Isotope Analysis Oxygen isotope analysis is a method often employed which does not require a visual examination of the shell structure. It is known that in the sea the ratio of the naturally occurring stable isotopes 18O and 16O changes according to temperature and that these isotopes are taken into the shell carbonate. Samples of calcium carbonate may be taken at close intervals along the direction of growth of a shell using a 0.5 mm drill and the variation in isotopes can be plotted to show a temperature related curve, which may highlight seasonal fluctuations. This can then be used to analyse age and season of death of the shell (Deith 1985; Shackleton 1973).

S.E.M. was used by Koike (1980) alongside acetate peels, in order to understand the seasonal exploitation of the clam, Meretrix lusoria in Japan. Here, S.E.M. was used to examine both the finer details of growth increments, and also to observe the cross-lamellar structure of the outer layer of the clam.

There are however, several criteria which must be met before isotopic analysis can be used for archaeological analysis. Shells with a relatively short growing season will be excluded from this study because they cannot provide seasonal information. There also needs to be water temperature variation in order to detect seasonal changes but huge variations in salinity, for example as occurs in estuaries where there is an influx of freshwater, may cause problems. Postdepositional isotopic exchange may also occur and it is important to know whether there have been any secondary

Acetate Peels Variations on a theme tend to exist with this technique but the basic steps outlined by Kennish et al. (1980) and followed by many researchers are, 1) embedding the material in a resin to prevent fracturing during sectioning, 2) sectioning the shell along the desired axis using a saw, 3) grinding the section and then polishing it, 4) etching the polished surface in acid, 5) once etched satisfactorily, washing the surface clean of 30

METHODOLOGY to the saw blade and a second cut made 200 µm from the surface of the blade. The slide can then be ground by hand until the required transparency is achieved. A cover slip or temporary cover may be applied.

acid then drying, 6) finally, the surface is flooded with acetone and a piece of acetate is applied to this surface. Once the acetone has dried the peel is removed from the surface and mounted onto a glass slide. This technique provides a negative of the section which then can be analysed under the microscope.

The only archaeological example which appears to use this method is the recent work by Quitmeyer et al. (1997) on the hard clam, Mercenaria spp.. Experiments proved it possible to produce a section without embedding in resin. The samples were cut using a water-cooled lapidary saw with a diamondimpregnated saw blade or with a Mark V alumina oxide blade. Sometimes the cuts were sufficiently smooth but in some cases further polishing was required using 240-, 400-, 600-grit, wet and dry emery papers and 1µm alumina microgrit. The cross-sectioned shell surfaces were then examined either by eye or microscopically, at 10x or 20x magnification.

Not all researchers embed their material in resin prior to sectioning. Coutts and Higham (1971), and Coutts (1974) sectioned the cockles first, and then embedded in plaster of paris. Deith (1983) found it was possible to take acetate peels from cockle sections without embedding at all, even though her methods had been adapted from previous work where resin was used; Koike (1980), who used a polyester resin and Richardson et al. (1979). Methods of sectioning also vary from using a carborundum cutting wheel (Deith 1983), to using a hacksaw (Richardson et al. 1993). In the case of the work on the American oyster neither resin nor sectioning was employed (Kent 1988; Custer and Doms 1990). Acetate peels were taken from the exterior surface of the hinge, where macro-bands are visible. Although this is an irregular surface, it is etched and then flooded with acetone. A cellulose acetate solution is then applied and left to dry.

Experiments with Methodologies The primary aim of the research was to use a method for analysing ontogenetic growth which enabled an interpretation of the season of death to be made. The work by Richardson et al. (1993) provided the “first-ever estimates of the age and growth” for Ostrea edulis. It had been shown that this oyster produced an annual line in its structure in March/April time giving an anchor point from which to work from. As there did not appear to be any finer resolution in the structure, such as micro-lines, it was imperative that growth patterns produced in the rest of the year and variability between months and seasons were fully understood. It was also essential that the growing edge was not damaged because the amount of growth between the last annual line and this edge was vital for interpretation.

Prior to etching the section may be polished, again in a number of ways, such as using carborundum sheets and aluminum (Koike 1980) or “Brasso” (Richardson et al. 1979). Varying solutions of hydrochloric acid are generally used to etch the prepared surface. Kent (1988), however, used sodium hypochlorite acid for samples taken from acidic soils, and acetic or hydrochloric acid for samples removed from alkaline soils and Richardson et al. (1993) used Decal, a histological decalcifying agent for etching Ostrea edulis. It appears that the solution of acid and times for etching depends on the material, but the aim is that definition of the microstructure can be seen. The sample is then either pressed onto acetate film (Deith 1983), or an acetate strip is laid onto the surface, after applying acetone (Richardson et al. 1979).

There was no question that the area to be analysed was the hinge. It had been shown with Crassostrea virginica (Kent 1988) that this was the only part of the shell which clearly showed banding, and this was also true for Ostrea edulis (Richardson et al. 1993). The hinge of Ostrea edulis is much smaller than that of the American oyster and the resolution would be poor if the approach by Kent (1988), where peels were taken without sectioning, was used. As the work of Richardson et al. (1993) was successful in identifying annual lines, it was decided that sectioning the hinge of the oyster at right angles to the growing edge and examining the structure in section would be more fruitful.

Thin Sectioning Although thin sectioning has not been particularly feasible in the past, it may now be possible due to the introduction of low speed saws meaning that specimens are less likely to split along growth boundaries. As well as showing the features which can be identified using acetate peels, thin sections show variation in transparency, pigmentation and crystallographic orientation. High magnification studies can make use of the thickness of the thin section to make limited observations in three dimensions and unlike acetate peels, which have a surface relief to protect and a tendency to curl up, they are easier to store and to study (Clark II 1980, 603).

Experiments with various methods were made. Although Kent (1988) claimed that staining gave undeniably better resolution than acetate peels, this may be due to the fact that the hinges were not sectioned prior to applying the acetate solution and the irregular surface would create uneven peels which are difficult to analyse under the microscope. The staining method did appear to be fairly problematic and Coutts and Jones (1974) attempted it but reverted to X-rays instead. This approach was therefore not attempted on Ostrea edulis.

There are variations in technique which largely depend on the material in question. Clark II (1980) states that a section can be made, without embedding in resin if using a low speed saw. The surface is then ground, cleaned and cemented to a petrographic slide. The slide should then be mounted parallel

31

CHAPTER 4 Although oxygen isotope work has been fairly successful in archaeological studies of this kind, it was felt that the archaeological material to be used in this study was not suitable for this technique. One of the sites, Dyngby, was found to be very waterlogged on excavation, and there is the possibility that the sites were inundated by the sea at various points in their history. It is possible therefore, that secondary changes of isotopes may have taken place since the formation of the shell mounds (Deith 1985). It is also extremely likely that all the shells from the archaeological sites were originally gathered from estuaries, which have a tendency for substantial fluctuations in salinity which affect isotopic ratios. Indeed, analysis made on the periwinkle (Littorina littorea) from Norsminde, one of the main Danish sites sampled in this research, showed that the technique could not be used for estuarine locations such as this (Deith 1985, 125).

boiled for an hour to kill all bacteria and viruses. They are then left to dry on racks. Obviously any flesh that had remained attached to the archaeological shells had long since rotted, but the valves have to be cleaned to remove silt particles. They are placed in a ultrasound bath for 5 minutes in water of 50 °C, and then laid on drying racks.

Sectioning the Valves Although the hinges of the left valves are slightly larger than the right ones, the latter are selected for sectioning. Having experimented on the left valves it was found that these often contain more cavities, which break up the structure and hinder interpretation. Their cupped form also make sectioning more problematic. The right hinges are sorted and those which are broken or have grown on a skew tend not to be selected, as the earliest annual line does not appear in the section, see figure 4.1. As it is not always possible to select a perfect sample it is noted after sectioning whether the section line runs through the tip of the hinge and whether the hinge is damaged in any way so that this can be referred back to when analysing the thin sections.

Some examination of the structure of Ostrea edulis was made using S.E.M. methods. Impregnated, sectioned hinges were prepared as described above, but the technique is expensive and it was found that the degree of resolution required could be obtained using an optical microscope. It was also noted by Burke (1993, 45), that the resolution of looking at dental cementum increments in archaeological mammal teeth under S.E.M. was comparable to results from using polarised light microscopy.

hinge Left section

Experiments employing acetate peels were also attempted. The hinge of the shell was sectioned using a water-cooled slow speed saw (Isomet 1000, Buehler Ltd.) with a diamond wafering blade. One of the sections was then impregnated in the epoxy resin Epothin, vacuumed for 20 minutes in a vacuum chamber and allowed to cure for 8 hours. The sectioned surface was ground using grit papers and then polished with 3 µm diamond paste. This surface was etched in 0.1 % hydrochloric acid for about 10 seconds, rinsed and dried. The surface was then flooded in acetone and a strip of acetate was lowered onto the surface and left to dry.

C

A

B

Right section A

B

adductor muscle scar

Although the peels can be mounted between a slide and a coverslip, it was found that they tended to go crinkly as they dried. They did show annual lines but acetate peels are negatives of the surface of the structure and obviously do not replicate the differences in colour which can be seen in section. It was therefore decided that the technique of thin sectioning should be applied. Not only would these enable closer examination of the structure between annual lines but they also last longer and are easier to store.

horny prismatic scales

Preparing the Oysters

Figure 4.1: View looking down on the inside of the right, flat valve of the oyster. The hinge has grown on a skew making the sectioning process problematic. Line a-a indicates the initial cut which separates the hinge from the body of the shell. Line b-b indicates the section cut at right angles to the growing edge (c). It can be seen that this misses the first year line at the tip of the hinge because of the skew in growth. In this case the right section would probably be chosen for thin sectioning because after some of the shell had been ground away all the annual lines would be caught in section.

A modern control sample of oysters was used in this research, as well as archaeological oysters, and both samples have to be prepared prior to sectioning. The modern oyster shells have to be cleaned vigorously. The flesh is removed and later incinerated and the shells are bagged according to site and

The valves are firstly sectioned across the shell so that the hinge is removed from the extraneous shell and so that the section can sit inside one-inch moulds for the impregnation stage. The hinge is then sectioned at right angles to the growing edge using a low speed saw (Isomet 1000, Buehler

Method for Thin Sectioning Ostrea edulis

32

METHODOLOGY Ltd) with a diamond wafering blade. A table top attachment is fitted to the saw which allows each shell to be held by hand whilst cutting, ensuring complete control. It is therefore possible to cut exactly along the desired axis, from the tip of the hinge through to the growing edge. The slow speed of the saw and quality of the blade prevents much damage to the section taking place and usually no fracturing along growth boundaries occurs. If however, the hinge is sectioned after resin impregnation it becomes much harder to see exactly where the section should be made and the sample has to be mounted in a vice on an arm attachment, thereby losing control over sectioning along the desired axis. It also takes much longer to section because the resin has to be cut through as well.

It has been found that once the samples are removed from the chamber they should be left to cure in an area of constant, and preferably fairly low humidity and temperature. Various problems arose initially when the samples were not left in these conditions. The resin either did not cure particularly well and after 8 hours had not set, or else it would cure far too quickly and set with bubbles incorporated within it. This tends to happen especially overnight in the winter when temperatures drop, in the high heat of summer, or on very humid days but problems with tacky resin can still occur in less extreme conditions too.

Preparing the Sections Once the resin has hardened the samples are removed from the moulds and labelled with a diamond pen and a water resistant marker. Ten resin blocks at a time are placed section face down in a holder, which exposes the lower part of the block. This is attached to a Motorpol (Buehler Ltd.). Metallographic grit papers are stuck to the 12 inch platen which is then attached to the Motorpol. This is then revolved under a light jet of water and the holder lowered onto the paper thus enabling the sectioned surface of the shell to be lightly ground on successively fine papers. A fairly coarse grit paper of P600 is used initially, followed by papers of P800, P1200 and P2500 grit respectively. Finally the platen is removed and another is used, this time with a texmet polishing cloth attached. The surfaces of the blocks are washed, acetoned and dried and then are polished using 3 µm diamond paste lubricated with metadi fluid, for about 3 minutes at a low speed.

Impregnation Cutting through the hinge produces a right and left section. The better (unbroken or most complete) section is selected, cleaned with acetone to remove grease and water and dried under a hairdryer. The section edge is then placed face down into a one-inch plastic mould. This has also been dried and cleaned with acetone and then wiped with release agent (Buehler Ltd.) ensuring that once the resin block has hardened it can be easily removed. Next, Epothin epoxy resin is prepared by mixing 100 parts resin with 36 parts hardener. This has to be an absolutely accurate mix in order for the resin to harden correctly and therefore the parts are weighed out in disposable beakers on an electronic scale, and mixed thoroughly with wooden stirrers. The resin is then poured into the moulds and these are placed into a vacuum chamber for 20 minutes at -20 inches/Hg. They are then removed and left to cure in an environment of constant humidity and temperature for at least 8 hours.

The time and speed of each grinding event depends on the samples in the holder. During the resin impregnation process some resin settles between the sample and the bottom of the mould. This therefore has to be ground away before the shell is reached. At this first stage the holder is continually removed from the Motorpol, and the samples checked. Once the excess resin has been removed, the samples are washed and acetoned and then ground on a finer paper. The length of time given for each grit paper, the pressure of the samples on the platen and speed of rotation can be adjusted depending on observations made throughout the process. The aim of the grinding is to remove any damage caused to the sample whilst sectioning, and to attain a glass like surface, but at the same time attempting to remove as little of the sample as possible. It was found initially, that too much material tended to be ground away losing much of the sample, which generally makes the thin section impossible to interpret. Some “remakes” were made which basically took a second thin section from a block. The final result was a distorted picture of the structure and erroneous interpretations, and it became clear that the thin section had to be taken from the centre of the hinge at right angles to the growing plane.

Other resins and vacuuming times have been experimented with. The resin Metset was originally employed. It is a relatively inexpensive glass clear resin with low exothermic temperature but it is fairly viscous and thickens quickly. This had been used by Richardson et al. (1993) but simply for holding the sample in a block which facilitated handling and the taking of acetate peels, and the samples had not been vacuumed. Epoxy resins Epotek and Epothin were also tested and vacuuming was carried out in order to expel all air from the sample because air bubbles within a sample can weaken the bond to the slide which causes problems at the final sectioning stage. Both these resins worked well with the material. Epothin was a slightly yellow resin and Epotek was clear but the former is cheaper and at the final stage when the specimen has been thin sectioned the yellow tinge is negligible and does not affect interpretation. Epothin, therefore, is mainly used. Different vacuuming times and pressures were also tested. Generally any time between 15 and 20 minutes tends to work well when using the one-inch moulds, although if the moulds and samples were larger, then 20 minutes is better. The aim is to expel all air from the sample and resin without cooking the resin, and this can be achieved by monitoring the process to check that the resin is not bubbling.

To obtain a closer control on how much sample is ground away the blocks can be prepared by hand. This technique, however, has several disadvantages including being very time consuming. In addition, grinding and polishing by hand may

33

CHAPTER 4 produce curvature due to differential pressure which hampers the bonding process which requires a completely flat surface.

varies from section to section and is monitored by eye and repeated checks under a polarising light microscope. The sample is lastly ground carefully on P2500 paper which removes any final damage and this final thin section is usually between 10 and 25 µm thick. The structure of the shell should be clearly observable under a polarising light microscope. No coverslips are applied in case further grinding or polishing is deemed necessary in the future.

Bonding to a Slide After polishing, the samples are removed from the Motorpol holder and cleaned with acetone. Glass slides, 76mm by 12mm and 1.2-1.5mm thick are frosted on a Petrothin thinsectioning system (Buehler Ltd.) to ensure complete flatness on which to bond the sample. Any curvature of the glass means the resin block does not bond well to the slide because air bubbles get beneath the sample. A very small drop of adhesive Loctite 322 is applied to the centre of the sample and the slide gently laid over and pressed down ensuring that no air bubbles are trapped between the resin block and slide. These slides are then placed under ultra-violet light for five minutes for the glue to cure.

Summary There are five different methods commonly used in archaeological study for examining the skeletal record of shells in order to ascertain information pertaining to season of death. In this study they have all been considered but thin sectioning was chosen as the most appropriate for Ostrea edulis even though acetate peels are usually the most popular. Thin sectioning was regarded as superior because the article under examination is a slice of the shell and this retains the colour and structural patterns whereas an acetate peel is an impression of an etched section in negative form. This may be a technique that works well on other species such as the cockle where tidal lines are registered, but it will be illustrated in chapter 5 that thin sections are ideal when examining the skeletal record of the oyster. Here a high resolution is required to identify structural changes and these can then be correlated with seasonal and non-periodic events by using a large modern control sample.

The bonding stage is very important to the whole process, for a bad bond tends to result in a discarded sample, or a re-run of the grinding, polishing and bonding process. It is imperative that both the slides and the samples are ground for a completely flat surface. Samples which are bonded to slides that had not been frosted tend to peel off eventually or large air bubbles appear which make interpretation very difficult, if not impossible. Using larger moulds also causes problems, for the bigger the area to be bonded, the greater the chance of air bubbles getting between the slide and the sample. Different types of bonding agent were also experimented with. Resin was used initially and usually this was the Epothin that was used at the impregnation stage. A small drop is placed on the sample and the slide lowered carefully onto it, ensuring that the resin spreads across the whole surface without incorporating air bubbles. The samples are then placed under a “bonding jig”, which applies pressure, for 8 hours. This theoretically prevents air getting under the slide as well as aiding bonding. It was found however, that even though pressure was applied, air bubbles often appeared in the resin bond and the slides tended to weaken or crack. The resin also has to be mixed and this process is time consuming. Technovit, another type of glue, was also tried. This cures much more quickly than Loctite 322, in fact practically as soon as it is placed on the sample, and so any air which does get between the block and the slide can not be forced out of the glue before it becomes too tacky.

The Thin Section Once the sample has bonded to the slide a thin section is made by cutting most of the sample off the slide using the Isomet 1000 thus leaving a thin section of approximately 50 to 100 µm. This is still not thin enough to clearly see the microstructure of the shell so the sample is then ground away further using grit papers P600, P800, P1200 and P2500. The slide is placed in a holder with the sample face down and held by hand over a revolving platen with attached grit paper. P600 or P800 papers are used first to remove most of the excess material and the sample is then ground on the finer P1200 paper until the required thickness is achieved. This 34

CHAPTER 5

Interpretation of the Modern Control

Once the modern control sample had been sub-sampled the shells were thin sectioned, as described in the last chapter, and then analysed. The principle objective was to develop a method of interpretation which allowed season of death and age of the oysters to be assessed accurately. Firstly it was necessary to identify annual lines in the structure. It was known from the work of Richardson et al. (1993) that these existed but it was necessary to use a modern control sample to monitor the range of time in which the lines may form, and how they may vary from different locations. This was crucial for the study of seasonality because interpretation completely relies on being able to anchor the line to a particular point in the year. The amount of growth between this line and the growing edge may then be used to assess the season of death of the oyster. The thin sections were analysed under a polarising light microscope. Firstly they were viewed under a low magnification of around x10, and then under a higher magnification of about x50 to look at various lines or parts of the structure in further detail. It was found that different lines could be identified, and after a length of time studying the thin sections annual lines could usually be distinguished from other disturbance lines. Notes made from these observations can be found in Appendix 1. These also include measurements, taken using a graticule, of the distances between annual lines, and the last line and the growing edge. Although measurements were taken it was felt that they were in general fairly useless when attempting to ascertain seasonality. Instead it was found that the month of death can be judged by eye. The amount of growth since the last annual line was visually compared with past bands of growth and observations of changes in colour and the patterning of the structure were used. This chapter will present the results and observations made when identifying annual lines and disturbance lines and anchoring these to points in the yearly cycle of growth. Differences between the locations and sites will be presented. A detailed description of how measurements were taken and then used in an attempt to determine season of death will be given, together with the problems involved in this approach. The preferred qualitative method of examining the incremental structure of the shell will then be demonstrated using images and illustrations taken from the samples. The images in this chapter are shown are in black and white but may be seen in colour and more detail on http://archaeology.ncl.ac.uk/other/publications/jas1 (May 2002).

CHAPTER 5

Annual Lines and Disturbance Lines The “classic” annual line For oysters from sites and locations where annual lines and disturbance lines are similar in form, it becomes imperative to analyse samples every month in order to understand the changes in incremental growth that occur through the year. If, for instance, with the shells collected in August there are a large number of samples which have lines very near to the growing edge it is known that these lines are not likely to be annual lines, (usually formed in spring), and therefore they must be disturbance lines, possibly caused by spawning. This then leads to further investigation under higher magnification which results in the identification of differences between the two types of line. This observation of line structure, and patterning and colour of the incremental growth between lines leads to confident interpretation of annual lines.

The work by Richardson et al. (1993) shows that annual lines can be identified in the structure of the Ostrea edulis, and that these lines form in the spring. Oysters from wild and cultivated stocks had been sampled from Whitstable, Bramble Bank in the Solent, Tal-y-foel in the Menai Strait, Argyll in Scotland, the River Blackwater in Chelmsford and the River Fal in Cornwall. Here, a general description of the appearance of annual lines is given, although it is noted that annual lines are clearer in the oysters from Argyll and the River Blackwater than those from the other sites. These lines are shown to be observed in both the prismatic inner shell layers and the hinge area. Those in the hinge are also seen to extend into the ligostracum where they form a series of finer lines. It is noted that at the boundary between the ligostracum and inner shell layer the growth lines often coincide with a small depression or cleft. Other lines are described as “not true growth lines”, composed of chalky deposits in which were scattered small crystals.

The overall patterning and colour changes through the shell structure are examined through polarised light. Firstly a low magnification is used so that the whole section can be seen in full and the polarising light is rotated to accentuate certain features. The bands between annual lines, each representing a years growth, tend to show a patterning of colour, denseness and incremental growth which is often crudely reproduced from band to band. The width of these bands, however, are not uniform, tending to decrease slightly each year.

Whilst analysing the control sample of thin sections from Southampton, Whitstable, Truro and Chelmsford, in this study it became clear that a classic annual line rarely existed. It seems as though there are very few rules that can be constructed for defining an annual line, as they appear to change depending on the location and site. Often disturbance lines make interpretation all the more harder. It is clear that a very large sample size and a great deal of experience is needed before confident recognition of annual lines and disturbance lines can be made, and from this season of death deduced.

Often the annual line itself will look like a thin break in the structure of the shell. Those in figure 5.2 can be described as pale lines delimited by darker structure either side. These annual lines also appear to have a single dark line adjacent to their left edge. Alternatively, annual breaks may be represented solely by a dark line. In whatever form they appear, annual lines always extend right up to the boundary and often into the ligostracum. A cleft in the boundary may occur, although this tends to be of varying greatness, depending on which location and site the sample is from.

To illustrate this point, a comparison of initial and final interpretations for the samples from Whitstable was made. The shells from Whitstable were some of the first samples thin sectioned and having completed the process, notes on the structure and number of annual lines were made. Over a year later, having completed the thin sections from all the locations and analysed examples from all the months of the year with varying numbers of disturbance lines, the Whitstable samples were re-analysed. The comparison showed that the original notes were, in many cases, erroneous although at the time it had been acknowledged that there was a discrepancy. The Whitstable oysters were known to be 3 or 4 years of age but the estimates which were being made were usually around 6 years old. It was clear that disturbance lines were also being counted, however these lines in the Whitstable oysters bear a striking resemblance to the annual lines, see figure 5.1.

The sections from Chelmsford tend to be comparatively easy to interpret. As figure 5.2 shows, the annual lines are clear and they coincide with a cleft in the boundary. Figure 5.3, on the other hand shows an example from a site in Truro where the annual lines are not so well defined. Here they occur as darker lines, with very little dipping in the boundary. Disturbance lines also occur in the bands which makes interpretation even harder. Annual lines in samples from some sites in Southampton tend to be as difficult to analyse.

36

INTERPRETATION OF MODERN CONTROL

Figure 5.1: Sample W.1.14.R, collected from Whitstable in April. This shell appears to have 7 lines, all very similar in appearance even under higher magnification. After careful analysis, however, lines 2, 4, 6 and 7 were classed as annual lines, and the remaining lines as disturbance lines. The holes in the shell around the bottom margins have been made by boring predators.

37

CHAPTER 5

Figure 5.2: This shows a section of a shell, C.3.E.18.R, collected in May from the River Crouch, Chelmsford. It is a slide made from the right hand side of the sectioned valve, and the most recent growth can be seen at the growing edge, on the left of the structure (this is reversed on a slide which has been made from the left hand side of the sectioned valve, e.g. figure 5. 3). It is an example of a shell with a very clear structural pattern, and 4 lines have been identified, 1 having just formed at the edge. These are annual lines and they can be seen to extend into the ligostracum. There are clefts or dips in the boundary (the point at which the ligostracum joins the shell structure) where the annual lines meet it. The topography of the boundary tends to rise and fall between annual lines. The incremental growth between 2 annual lines is termed a band, and disturbance lines, patterns in colour and changes in structure can be observed in these.

38

INTERPRETATION OF MODERN CONTROL

Figure 5.3: This shell, T.12.R.11.L, was collected in April 1997 from the River Fal, Truro. It has 3 annual lines (1-3) which appear as dark lines, and these continue into the ligostracum. It also has 2 disturbance lines (D) in each band. These are much thicker and darker than the annual lines.

39

CHAPTER 5

Disturbance Lines

Differences between Locations and Sites

Three main types of disturbance lines, physically distinct from each other, were identified in the structure of Ostrea edulis. These have been termed the “conchiolin line”, the “mid-lines” and “others”. The specific reason for the occurrence of these disturbance lines is not always clear. It is likely that they are formed because of some sort of disruption in growth and therefore their appearance may differ depending on the nature of the disturbance. As described in chapter 2 many internal and external factors can affect growth, from episodes of spawning to predator attacks.

There are certain very clear differences between the structure of the oysters from the four locations. The shells from Chelmsford on the whole have very “clear” structures with very little disturbance, mirroring the exterior of the shells (see chapter 3). The annual lines are clear breaks in the structure, which join the boundary with a cleft, see figure 5.2. The samples from site A were exceptionally clear. Most of the shells exhibit mid-lines but these tend to be much fainter and easily discernible from the annual lines. The features which do distinguish the sites from each other, however, are the conchiolin lines and mid-lines. The samples from site J tend to be riddled with conchiolin lines, suggesting a great deal of disturbance, and they also have several mid-lines between each annual line. The others only ever have a couple of disturbance lines. The shells from site D and site E in the River Crouch occasionally have red lines which have just formed after the annual line and the shells from site H are not always particularly clear, often having several disturbance lines.

Conchiolin lines are characterised by thick lines of a yellowy greenish material which rarely extend up to the boundary, see figure 5.4. This type of line would never be mistaken for an annual line. They are composed of conchiolin, a fibrous insoluble protein which forms the basic structure of the shell. This material is laid down by the mantle when the nacreous layer of the shell is damaged. This kind of damage may occur at any time of the year and could, for example, be attributable to a boring predator.

The shells from Southampton and Truro are much more similar to each other, and in general exhibit a lot more disturbance in their structure than those from Chelmsford. The three Truro sites, the river Helford, site R and site O do not demonstrate much variation, probably because the locations are close to each other and the conditions are similar. The annual lines are often fairly difficult to distinguish from the disturbance lines. Usually the disturbance lines are thicker and darker than the annual lines, see figure 5.3. The oysters from Southampton are much the same although they tend to be slightly clearer, the annual lines being cleaner breaks than those from Truro, see figure 5.6. They often vary within a site, some having very clear structures whilst others have many conchiolin lines and midlines. It has already been noted that those shells from Whitstable are harder to analyse because the mid-lines are so similar to the annual lines.

Mid-lines are the type of disturbance line which cause the most problems in interpretation because they can easily be mistaken for annual lines. They have been termed mid-lines because they usually occur roughly in the middle of the band, between two annual lines. Often only one mid-line occurs in each band but sometimes two or more can be seen. They may coincide with a rise in the boundary between the shell structure and the ligostracum but sometimes they coincide with a cleft. Their structure may be obviously different from the annual lines, for example in figure 5.4 the mid-lines are dark and thick and the annual lines are distinguishable thin clean breaks. Sometimes, however, the mid-lines mimic the annual lines and appear as clean breaks but under careful scrutiny they are usually too thick or the clefts in the boundary are not pronounced enough, see figure 5.3. Alternatively, mid-lines may have dramatic clefts in the boundary which may have resulted from the nature of their formation, for example a harsh but brief storm. Other types of disturbance lines may occur infrequently. One such example is the unexplained red-orange lines which occasionally occur in some of the specimens from the sites of Purleigh and Althorne in the River Crouch at Chelmsford, see figure 5.5. These appear to have formed not long after the previous annual line and they do not extend up to the ligostracum boundary. It is, however, unclear as to the reason for their formation but similar lines have been identified in some of the archaeological samples as well so it is unlikely that they are caused by modern day pollutants.

40

INTERPRETATION OF MODERN CONTROL

Figure 5.4: This shows the thin section of S.2.C.5.L. from Southampton and illustrates problems encountered with disturbance lines. The conchiolin lines are easily distinguished and in this example have mainly formed in the oysters first year (the left side of the shell), although there is one in the last year, near to the growing edge further down the structure. In this example mid-lines “a” coincide with a rise in the boundary, but “b” coincides with a severe cleft. The mid-lines can also be seen to look quite similar to the annual lines and careful scrutinisation under high magnification is needed to distinguish between the lines. This example also illustrates the cavities which may form in the shell structure, as described in chapter 2.

41

CHAPTER 5

Figure 5.5: This close up of C.12.E.11.L , collected from the River Crouch, Chelmsford shows disturbance in the form of red-orange lines which has occurred immediately after the annual lines 1 and 2 formed. Obviously these colours cannot be shown in a black and white image but the photograph does show 2 darker patches next to lines 1 and 2, as shown in the diagram. It is not known what has caused this pigmentation to occur but it has also been identified in some archaeological samples.

42

INTERPRETATION OF MODERN CONTROL

Figure 5.6: Sample S.5.E.17.L. was collected in May from site E, Southampton. There are 2 annual lines visible (1 and 2) and there is only 0.1mm of growth between line 1 and the growing edge. Although there is some disturbance in the most recent band the annual lines are easily distinguishable, being clean breaks in the structure with pronounced clefts in the boundary. This is especially clear under such high magnification (x50).

43

CHAPTER 5

Time of Formation of Annual Lines 1996. The table shows that 83% of this sample had formed an annual line by this time.

In the yearly cycle the growth of the oyster begins to slow down in the autumn months. In the winter very little shell is deposited and from the observations made of samples collected from December to March it appears that little or even no growth is occurring. In the spring it is likely that the increase in sea temperature triggers growth again, and the winter cessation followed by new spring growth can probably account for the annual lines. Because sea temperatures are likely to stimulate new growth it would seem likely that the timing of annual line formation may change not only from site to site but also from year to year.

Table 5.2 shows the results of tallies from Truro. Shells were collected on the 22nd and 23rd March 1996 and 17th March 1997, 22nd and 23rd of April and the 22nd May 1996. There were no samples collected in February. These results are fairly similar to those from Whitstable in that by two thirds of the way through April the majority of oysters (95% of April samples) have formed annual lines. In March only 36% of oysters have formed lines but towards the end of May there are no examples of shells which have not formed them. The samples from the Chelmsford sites were collected on the following dates: 5th, 7th and 27th February 1997; 18th and 19th March 1996 and 5th and 7th March 1997; 2nd, 9th, 10th, 22nd April 1996; 13th and 15th May 1996. Even by late February there is no evidence for line formation on the growing edge of any oysters, table 5.3. In March only 24% of oysters have formed an annual line. By April half the samples can be seen to have annual lines at the growing edges and by mid May all shells display a line.

To test exactly when these lines must form, every thin section for every shell collected in the spring months was examined in order to see whether a line had formed on the edge or not. Tallies are made for each location and each site. Any unclear samples are counted under “no” and any unreadable samples were discarded. Table 5.1 shows the results of tallying for Whitstable. All these shells had been collected on 19th April

Whitstable

April yes no 15 3

Table 5.1: Tallies counting whether annual lines were observed or not on the growing edge of oysters from Whitstable.

March yes River Helford Site O Site R Total

1 3 4

no 5 2 7

April yes no 3 7 8 1 18 1

May yes no 3 4 7

0

Table 5.2: Table showing the tallies of annual lines observed or not on the growing edge of oysters from the sites of Truro.

The Nass Purleigh Middleway Althorne Creek Bench Head Total

February yes no 6 1

0

1 3 11

March yes no 5 3 2 2 2 1 2 4 13

April yes no 2 2 1 1 1 2 3 6 6

May yes no 5 2 2 1 10

0

Table 5.3: Tallies of annual lines observed or not on the growing edge of oysters from the sites of Chelmsford.

44

INTERPRETATION OF MODERN CONTROL

February yes Site B Site C Site E Site I Site J Site K Site H Site D Site F Site L Total

0

no 1 1 1 1 1 1 1 4 1 12

March yes no 1 2 1 2 2 2 2 2 3 6 2 2 14 13

April yes no 1 1 1 2 1 1 1 1 1 1 1 6 6

May yes no 1 1 4 1 1 1 1 1 3 1 15 0

Table 5.4: The tallies of annual lines observed or not on the growing edge of oysters from the sites from Southampton.

The samples from Southampton were collected on 13th February 1996; 4th March 1996 and 24th March 1997; 25th April 1996 and the 28th May 1996. Once again the data shows that no lines have formed in February and by May there are no examples which have not formed annual lines, table 5.4. In March 52% and in April 50% of oysters have formed lines. Site F perhaps stands out slightly in that 75% of the March sample has formed an annual line. This is an above average result but the other sites in the area, site L and site D, do not reproduce this pattern and the total sample size is very small.

said to form in March and April. These months were therefore used an anchor point in order to ascertain the month of death of the oyster.

Seasonality Measurements Season of death of a species can, in theory, be calculated by measuring the proportion of growth since the last annual line and comparing this to an average year of growth calculated from previous years. This approach was used on the American oyster, Crassostrea virginica, (Custer and Doms 1990; Kent 1988). Before directly applying this technique to a different species certain considerations have to be made. Firstly the method used for examining the structure involved taking acetate peels from the surface of the hinge without cross sectioning the shell, see chapter 4. Measurements taken from thin sections will therefore be taken from a different plane. Secondly, this method is only likely to work if the oyster grows fairly consistently from year to year. There is usually some degree of variation and this therefore means that the samples being measured must have at least two years growth from which to calculate a mean years growth.

It can be seen that on average annual lines appear to form after February and before May for all the locations and sites. Any finer resolution cannot be gained from this data because the sample sizes are too small. When Richardson et al. (1993) attempted a similar analysis their results were similar. Ten spat (oysters less than a year old) were collected each month between February and July 1991 from the Menai Strait, in North Wales in order to determine formation time of the first annual growth line. No lines were visible in the shells sampled in February but by July a line was clearly visible. Growth of the hinge was said to begin during March and April and this rapidly increases in May. It was said to be at this time that the growth line first becomes visible in the hinge (Richardson et al. 1993, 497). These observations led to the conclusion that in the Menai Strait the first growth line was laid down in February and March at a time when water temperatures are at a minimum of 6 °C, and those shells collected from the Blackwater during March 1991 also showed evidence of the deposition of a line at this time. Those collected from Bramble Bank in the Solent had deposited a small amount of growth since the last growth line (Richardson et al. 1993, 499).

Kent (1988) identifies annual lines on the exterior of the hinge. Using an ocular micrometer on a dissecting microscope, or a proportional ruler, two types of measurements are made; a) the distance between the inner edge of the hinge and the last annual line, and b) the distance between the annual lines for the last two complete years. This latter measurement means that average yearly growth can be calculated for each sample by adding the growth for each year and dividing by 2. The relative amount of growth since the previous winter is then calculated by dividing the measurement of growth between the last line and the growing edge by the average. Custer and Doms (1990), investigating

Although there are physical differences on a macro-scale (chapter 3) and microscopic scale (above) between oysters from different sites and locations, the range of annual line formation is the same for all. In general annual lines can be

45

CHAPTER 5 specimens from Delaware Bay, term this a “relative growth index”. Using these calculations histograms are constructed. It is noted, however, that standard deviations get larger for samples collected later in the year. This shows that there is a large amount of variability in shell growth and rather than interpreting the specimens to the nearest month, the seasonal identifications of spring, spring-summer, summer-fall and late fall-winter are made. Kent (1988) uses cumulative frequency plots to present his results. A tri-modal distribution of relative growth from the archaeological site of “Large Circular Trash Pit” is interpreted as showing May, September and December gathering.

ligostracum meets the shell matrix. This is not always a flat plane and therefore some measurements, especially those across older bands are not particularly accurate, see figure 5.7. A relative growth index is calculated from these older years but it is also known that oysters do not grow at a uniform rate throughout their lives. The amount of annual growth decreases as they age, but they may also experience harsh and adverse or extremely good environmental conditions which will all affect the growth patterning.

Averaging and standardising growth line data in seasonality studies has, however, been shown to be normative and liable to produce erroneous results, (as discussed in chapter 3; Claassen 1991). Basic assumptions about shell growth are shown to influence the prediction of the season of harvest. Large growth controls show firstly that shells do not respond to growth stimuli identically and secondly, that timing of these stimuli is not predictable each year. The mean of the growth data does, however, form a pattern and such standardised yearly growth patterns are often used in assigning a harvest time to individual shells. Claassen illustrates this by taking 5 modern control sample shells as an example. A relative growth index is calculated and 5 very different results are produced. The researcher who views growth in a normative manner, looking at each one individually, interprets the information as representing several different seasons. Alternatively, a researcher who understands the variation found in each month realizes that in all 12 months the range of growth may be this large. This is then demonstrated by Claassen (1991) by stating that the sample of 5 shells had been harvested from an area of one square metre, one day in the month of June.

Figure 5.7: An illustration of a thin section of W.1.14.R. from Whitstable, see figure 5.1. This shows how measurements are made for each band: from the edge to line 2, from 2 to line 4, and from line 4 to 6. They are taken from the point at which the annual line meets the boundary. This can be problematic if the topography of the boundary rises and falls as much as it does in this example. Another major problem with the modern control samples of Ostrea edulis is that the majority of specimens are younger than three years old and therefore calculating a relative growth index is going to prove difficult. Before attempting this approach the measurements from the last annual line to the edge were taken for the three sites at Truro and plotted to see if these measurements could be used to estimate season of death, figure 5.8.

Measuring growth of Ostrea edulis Problems using and interpreting measurements, identified by Claassen (1991), are concerned with analysis and the archaeologists’ application of the data, but further obstacles arise from using a thin sectioning method for identifying seasonality. Problems at the sectioning stage, measurements across a skewed plane and differential yearly growth are all going to affect the relative growth index and consequently analysis.

As would be expected the amount of growth increases through the year until March when a new line forms and growth is measured again from this new line. There are certain anomalies such as the June measurements for Site R and the 3 shells with very little growth in October and December. If these are ignored and a best-fit line is imagined the graph would show that growth commences in March/April, there is a steady increase in May/June and then a sharper addition of growth up to September. From here the rate of growth becomes steadier. Unfortunately there are no readings for the months of January and February but it is known from other sites that there is very little additional growth in these months. A new line is then either formed in March or April and the cycle will start again. The range of measurements for the growth increment and the anomalies should, however, be taken into account. The greatest measurement is just over 2

The measurements are subject to a great deal of deviation due to the thin sectioning process, however carefully the specimen is cut. The shells are first sectioned across the hinges. The cut which is made attempts to section the hinge at a right angle to the growing edge but as mentioned in chapter 4 there may be difficulties in achieving this if the oyster has not grown symmetrically. The shell almost always grows on a skew and therefore older bands of yearly growth will not be sectioned at right angles to the growing plane. Measurements from the thin section are taken from one identified annual line to the next, at the boundary where the 46

INTERPRETATION OF MODERN CONTROL mm but the range within one month can be spread over 1 mm, especially later on in the year, in August, September, and October (even when the anomaly is not included).

each sample by adding these measurements and dividing by n, the total number of measurements. Finally the last measurement was made between the first annual line and the growing edge and the percentage of this growth increment against the relative growth index was calculated.

Taking a similar approach to Claassen (1991), if the five shells collected in August are examined the measurements would read 0.4, 0.7, 1.0, 1.2 and 1.6. If these are then compared to the measurements on the graph the reading of 0.4 mm would fit into any month from May-July, and the 1.6 mm reading could interpreted as being as late as December, (or even January or February).

It can be seen that the growth index can vary from anything between 1.55 mms to 3 mms. It should also be noted that in many cases the oysters are less than 2 years old and therefore the last increment of growth can only be expressed in terms of the previous years measurement. This is problematic as the measurement of growth tends to decrease every year, although anomalies do occur as with T.4.R.9.R which has produced a reading of 2.3mms for increment 3-2, and 2.6mms for increment 2-1. The data is presented in figure 5.9 where it can be noted that after May, ranges in the data for each month appear to be even greater using a relative growth index. For example, if a shell from this site was thin sectioned, the increments measured, a R.G.I. calculated and a percentage for the last increment given as 0.5, and then this was compared to the graph in figure 5.9, it can be seen that the oyster could have been collected in any month from June to the following March!

The relative growth index approach was therefore attempted to ascertain whether this would produce tighter monthly growth increment readings, smaller ranges and therefore more accurate seasonality assessments. Table 5.5 presents the measurement data for site R in the River Fal, Truro. Only those samples with 2 or more annual lines are included so that a relative growth index can be used. The annual lines are numbered from the growing edge back through the shell and the measurements are taken between these annual lines; if for example there are 4 annual lines, measurements are taken between the fourth and the third, the third and the second, the second and the first. A relative growth index is calculated for

Growth from last annual line (mm)

2.5

2

1.5

1

0.5

0

March April

May

June

July

Aug

Sept

Oct

Nov

Dec

Jan

Feb March April

Month of collection (1996 and early 1997)

Figure 5.8: Measurements taken between the last annual line and the growing edge of the samples from the River Helford (black squares) and site O (grey diamonds) and site R (empty circles) in Carrick roads, Truro for 1996 and early 1997. Measurements were taken in mm using a graticule.

47

CHAPTER 5

Month 22-March

22-April

22-May

2-June

29-July 19-August

9-September

1-October 2-December 17-Mar April

Sample T.1.R.8.R T.1.R.9.L T.1.R.11.L T.2.R.6.L T.2.R.8.L T.2.R.9.L T.2.R.10.R T.3.R.5.L T.3.R.6.L T.3.R.7.L T.3.R.8.R T.4.R.6.R T.4.R.8.L T.4.R.9.R T.5.R.3.L T.6.R.7.R T.6.R.8.R T.6.R.10.L T.6.R.12.L T.6.R.13.R T.7.R.7.L T.7.R.8.L T.7.R.9.L T.7.R.12.R T.8.R.5.L T.8.R.7.R T.10.R.9.L T.10.R.10.L T.11.R.4.R T.11.R.6.R T.12.R.7.R T.12.R.8.L T.12.R.10.L T.12.R.11.L

4-3

3-2 1.8 2

2.6

2.3

2.1

2

1.8 2.4

1.9

2-1 1.3 1.7 2.7 2.2 2.4 2.2 2.1 2.3 2.7 2.4 2.2 2.2 2.9 2.6 2.4 2.6 2.8 2 2.5 2.4 1.5 2.2 2.5 3.2 2 1.9 2.5 1.9 3 2.5 2.2 2.5 2.6 1.8

R.G.I 1.55 1.85 2.7 2.2 2.4 2.2 2.35 2.3 2.7 2.4 2.2 2.2 2.9 2.45 2.4 2.6 2.8 2.05 2.5 2.4 1.8 2.3 2.5 3.2 2 1.9 2.5 1.9 3 2.5 2.2 2.5 2.6 1.85

1-0 0 0 0 0.1 0 0.1 0 0.3 0.4 0.4 0.2 1 2.1 1.8 1 1.2 1.6 0.7 1.3 0.4 0.8 1 1.9 1.2 1.1 1.2 1.4 1.9 1.9 1.2 2 0.15 0.05 0.05

% 0 0 0 0.05 0 0.05 0 0.13 0.15 0.17 0.09 0.45 0.72 0.73 0.42 0.46 0.57 0.34 0.52 0.17 0.44 0.43 0.76 0.38 0.55 0.63 0.56 1 0.63 0.48 0.91 0.06 0.02 0.03

1.2

Growth as % of index

1

0.8 0.6

0.4

0.2 0

22- 22- 22- 02Mar Apr May Jun

29- 19- 09- 01- 02- Jan Feb 17- April Jul Aug Sep Oct Dec Mar

Figure 5.9: Graph showing the last increment of growth as a percentage of the Relative Growth Index, data from table 5.5. 48

Table 5.5: This table presents the measurements between annual lines, the relative growth index (R.G.I.) and the increment between the last annual line and the growing edge, also expressed in terms of a percentage of the relative growth index.

INTERPRETATION OF MODERN CONTROL November onwards interpretation is regarded as much more difficult in that very little additional growth will occur in these months. There are however, several markers which aid interpretation and certainly distinguish shells gathered in these months from those collected in the early autumn months. As growth is beginning to slow down, the top of the growing edge at the boundary between the ligostracum and shell matrix appears to dip downwards. This is why a cleft or depression in the boundary between ligostracum and shell matrix can be seen with each annual line. Often a small triangle of ligostracum appears at this junction, as if it has been pulled away from the main body. The patterning of the band and its width should almost look like a complete years growth, but not quite. Figure 5.14 is an example of a shell collected in late October. Here the structure is already beginning to show signs of dipping at the edge and a triangle in the ligostracum. In figure 5.15 the triangle of ligostracum is larger and the dip greater although judging from previous years the boundary has to dip over the edge a little further before a line will form.

Structural Observations A measuring approach is clearly problematic and is not used here in interpreting the control sample. Instead observations are made using patterns, colour and seasonal “markers” in the structure of the shell in order to ascertain the month of collection. These observations will be described in detail, month by month. There is sometimes some overlap between months, and this may result from the time in the month the shell was collected. It should be noted that the categories of “months” are only used as a frame of reference and do not directly relate to the growing patterns of the shell. The easiest period of the year to recognise is the time when an annual line has just formed. There should be an annual line right at the edge and a very small increment of growth will have formed past this line, approximately 0.5-0.1 to 0.2mms. This is the only time when measurements can be used reliably, because the standard error is so small. These examples are typically of an April, or more usually a May collection date. Figure 5.3 is an example of a shell which has been collected in April, and here a line has just formed on the growing edge (annual line no. 1). As has already been demonstrated however, a sample collected in early April may not have commenced growth and therefore may not bear a line. Figure 5.6 is a close up of the section of a shell which has been collected in May. A clear annual line is visible near the edge and there is only a very small amount of growth between this annual line and the growing edge, about 0.1mm.

Figures 5.16, 5.17 and 5.18 show examples of sections from oysters gathered in the months of December, January and February. These months are difficult to distinguish from each other except that the degree of dipping at the growing edge tends to become more pronounced and the structure of the band looks more and more like a complete year of growth. Examination under high magnification and moving the sample around under the polarising light tends to elucidate the problem. Figure 5.18, which shows a shell that has been gathered in February, has a very pale streak right at the growing edge. This has also occurred in the last band just before line 2 formed. A similar phenomenon has occurred in the oyster on figure 5.19 collected in March. Here a line can just be seen to be forming on the edge. Often in March the dipping is substantial and sometimes it appears as if the ligostracum is falling over the growing edge.

Samples from June and July show a larger increment of growth since the last annual line, see figure 5.10. If samples are collected in early July they may look similar to those collected in June. If however, they are collected towards the end of the month they may have just formed a mid-line, possibly produced during a spawning period. Figure 5.11 shows that a great deal of incremental growth has occurred in the couple of months since the last annual line (1) formed. There appears to be a line forming on the growing edge but the increment since the last line is not really wide enough for it to be another annual line forming. There is a faint mark halfway between this and the growing edge but the boundary appears to be rising in a similar manner to the last band. In this last band the boundary rises up to the second disturbance line, or mid-line. In this present year of growth therefore, the boundary topography and the fact that there is a line on the edge suggest that a mid-line may be forming.

Summary By analysing the thin sections of the sub-sampled modern control it is found that annual lines can be identified in the skeletal record of the oyster, and that these can be distinguished from disturbance lines. Although variability in oyster size and characteristics are shown to exist for the various locations and sites sampled, no difference in timing of annual line formation can be distinguished. It appeared that annual lines are generally formed in the months of March and April. In order to ascertain seasonality, observations as to changes in the structure and colour of the shell are made, rather than using traditional methods of measuring. This is of course only possible because thin sections are used. Examples of shells collected throughout the year have been used to illustrate the interpretative method used here. On completing the analysis of the thin sections it is felt that interpretation of ageing and seasonality on archaeological samples is possible due to the experience gained examining the large sample size of the modern control.

From August onwards interpretation becomes much harder. The shells collected in the months of September and August are structurally much the same. Mid-lines are usually present, followed by an increment of growth, figure 5.12. Although there will appear to be a fairly large amount of growth by this time of the year it should still look like an incomplete band when compared to previous years of growth in terms of colour and structure, figure 5.13. In October the rate of growth has slowed down but the increment from the last annual line to the growing edge should not quite look like a whole years growth. From 49

CHAPTER 5

Figure 5.10: Sample S.6.E.15.L, was collected in June from site E, Southampton. Here 2 annual lines have been marked and it would appear that there is a fair amount of disturbance between these. It can be seen that there is more growth here between the last line and the edge compared to figure 5.6, a shell collected in May.

50

INTERPRETATION OF MODERN CONTROL

Figure 5.11: Sample S.7.C.9.L was collected in July from site C, Southampton. The boundary is rising and it looks as though a mid-line may be about to form at the growing edge. The patterning is quite clear in this sample and the growth of the present year can be seen to be mirroring the last year. There are 2 disturbance lines in the last band, and the boundary rises up to the second one. In the present year one faint disturbance line can be seen, the boundary is rising and a second disturbance line looks to be forming on the edge.

51

CHAPTER 5

Figure 5.12: This is a section from sample, S.8.I.6.L, collected in August from site I, Southampton. It clearly shows 3 annual lines, (1-3) and 3 mid-lines (a, b, and c). There is some incremental growth which has occurred since the last midline “a” but compared with the previous years, not enough to mistake the band as representing a whole years growth.

52

INTERPRETATION OF MODERN CONTROL

Figure 5.13: This shows a section of a shell, S.9.C.12.L., collected from site C, Southampton, in September. This example illustrates how difficult interpretation can be for a shell gathered at this time of the year. There is no clear mid-line. Looking at the pigmentation however, it can be seen that towards the end of band 1 there is a change of colour from grey to browny-grey, (point a). A similar colour change can be seen in the newest band, (2), at point b, just by the edge. From this, and the fact that this band is quite a lot smaller than band 1, it should be deduced that the shell has not completed a whole years cycle.

53

CHAPTER 5

Figure 5.14: This sample, C.8.A.17.R. was collected from site A, Chelmsford in October. Four annual lines can be seen. The width of the last band is not great enough to represent a year of growth. The edge is beginning to dip over and a minute triangle is forming in the ligostracum; these are indicators that growth is slowing down. See also how the lines in the structure of the previous bands bend round more to the annual line, whereas they are straighter near the growing edge indicating that the yearly cycle is not quite complete.

54

INTERPRETATION OF MODERN CONTROL

Figure 5.15: This oyster, C.9.A.14.L, was collected in November from site A, Chelmsford. Three very clear annual lines can be seen. The edge is dipping over and there is triangle in the ligostracum. Judging from the last 2 years, however, the edge needs to dip over a little more before a line will form.

55

CHAPTER 5

Figure 5.16: This shell, S.1.L.10.R, was collected from site L, Southampton in December. It looks as though there is a line forming on the edge but this is a trick of the light. This line is simply the thickness of the shell, seen because of the angle of the cut, and magnified. Nevertheless the boundary appears to be dipping right over the edge and the estimate of month of death could easily be wrongly made by a couple of months.

56

INTERPRETATION OF MODERN CONTROL

Figure 5.17: This oyster, C.11.H.23.L, was collected from site H, Chelmsford in January. Again the boundary can be see to be dipping over the edge but no triangle is present. The cleft in the junction at the last annual line is fairly severe suggesting that the cycle is not complete for this year, the dipping not being great enough. A comparison of band size is no help, and it may be that a sample such as this would be interpreted as being collected slightly earlier in the year, such as in November.

57

CHAPTER 5

Figure 5.18: This oyster, S.2.C.5.L, was collected from site C, Southampton in February. Looking carefully at the patterns of colour, a pale streak can be seen right on the growing edge, especially further down, which is mirrored in the previous band prior to annual line formation. It should be determined that this shell is about to form an annual line.

58

INTERPRETATION OF MODERN CONTROL

Figure 5.19: This sample, S.13.F.15.L, was collected from site F, Southampton in March. The edge is dipping right over and a line can be seen to be forming. The annual lines in this sample are extremely clean breaks.

59

CHAPTER 5

60

CHAPTER 6

Blind Testing

The method of interpreting thin sections of oysters, outlined in the previous chapter, relies on observing seasonal markers in shell micro-structure by eye, and not on measurements of growth. This could be argued to be purely subjective, and the non-mathematical approach means that it is imperative to prove that correct interpretations of seasonality can be made. Blind testing on a control sample of known seasonality may be used to achieve this, and the accuracy of interpretation can be assessed by calculating the number of times the month or season is judged correctly. If a high success rate is achieved, the method of interpretation can then be applied to archaeological samples. Blind tests can be used in a wide variety of applications in archaeology. Recently, tests have been conducted on control samples of red deer teeth in an attempt to assess the accuracy of obtaining seasonality results from cementum using thin sectioning methods (Tina Dudley pers. comm. 1997). Blumenschine et al. (1996) have also conducted blind tests to assess the accuracy of correctly identifying bone surface modification. This was used to try and resolve controversy concerning the mimicry of marks by different actors and effectors, and also to elucidate methodological debates about the magnification and type of equipment needed in such analysis. Sample sizes of 20 to 30 specimens were used and a percentage of correct interpretations was calculated in each case. Inter-analyst correspondence between the three experts was made as well as assessing the accuracy of novices with less than 3 hours training. The aim was to produce an objective and reproducible exercise, rather than a subjective “art”. The authors attained near perfect results, achieving a 96.7% three-way correspondence in locating marks and a 99% accuracy rate for identifying known marks. The novices correctly identified 86% of classic but not necessarily conspicuous marks. In this research, blind testing was carried out, to an extent, throughout the period of manufacturing the thin sections of oysters. The final step in production was to check the quality of the slide under a polarizing light microscope and at the same time a mental note was made as to the probable month of death. Not suprisingly, as more thin sections were made over time, estimations of seasonality became more accurate. It was however noted that on some occasions, such as after a full day sectioning or on a Friday afternoon, the number of correct evaluations decreased. It would seem, therefore, that experience and high levels of concentration are needed to gain good results, as might be expected. Having completed 484 thin sections from the control sample and analysed them again, this time making notes and diagrams, two types of blind tests were set up. The criteria of both attempted to test the accuracy of assessing the seasonality, the age, and the provenance of the oyster. The difference between the two tests was that the first was to be attempted by me, and the second by a “novice”. This was to compare almost two years experience in producing and analysing thin sections of oysters against someone with no background in this work. As with the work of Blumenschine et al. (1996) it is believed that this technique of thin sectioning and interpretation is reproducible and should be accessible to people with little experience in this field. A self teaching exercise was therefore set up as part of test 2. A set of instructions with examples, and access to all slides and notes in the control sample was given. In this chapter both test 1 and 2 will be described in detail and the results presented. Finally conclusions are drawn as to how these results and method of interpretation may be applied to archaeological samples. The results of each run are documented in Appendix 2.

CHAPTER 6

Blind Test 1 Runs 1, 2, and 3

This test was administered by an undergraduate, trained in archaeozoology, who had expressed an interest in this research, and who was then to go on and be the novice in Test 2. The administrator chose a sample size of 50 slides. The slides were analysed three times (runs 1-3) over a period of a month to test consistency between runs. Although the same slides were used for each run the large sample size made it unlikely that interpretations would be remembered from one run to the next. To make it harder to recognize the thin sections, the order was changed and the slides re-numbered 150 each run by the administrator. Intensive analysis of archaeological samples between run 1 and 2, and a holiday between runs 2 and 3 furthered the unlikeness of being able to remember individual thin sections. Observations were made on the basis of seasonality, age and provenance of the oyster.

The test was repeated three times to assess consistency. The runs, however, were taken on various days of the week, following different periods of work to see if interpretation was significantly affected by these variables. Although levels of concentration cannot be quantitatively measured, the time of day and day of the week, the time taken to complete the test and astuteness was noted on each occasion.

Slide Selection

1.

The first run was carried out on Monday, February 9th 1998 at midday. The month prior to this had been spent analysing the modern control sample under the microscope and notes and diagrams had been made for each thin section. This had resulted in some eyestrain over this period but the observational technique was very fresh in my mind. The run took over an hour to complete, not including a half-hour interruption in the middle.

2.

The second run was performed a week and a half later on Friday 27th February 1998. During the period between the two tests the archaeological thin sections had been examined and again this had resulted in some eyestrain. Because analysis had changed from the modern control sample to archaeological samples it seemed harder to assess which location the oysters originated from. This run took an hour to complete.

3.

The third run was conducted a week and a half later on Monday 10th March 1998. This followed a weeks break from analysing thin sections and microscopy so I had no eyestrain at all. This run took just under an hour to complete.

The administrator made a selection of 50 slides from the 484 in the control sample, following these guidelines: •

•

•

•

Take examples from all 4 locations: Chelmsford, Truro, Southampton, Whitstable, but not necessarily in equal proportions and not so many from Whitstable (as these were all collected in April). Do not add any archaeological thin sections. Take a cross section of examples from the different sites from the above locations, although not necessary including all. Some sites are easier to analyse than others, see for example the oysters from site A, Chelmsford which have clear structures, whereas those from site F in Southampton are usually difficult to interpret because of the vast numbers of conchiolin lines. Check the slides with the notes and diagrams made so that those which are very badly made or have broken edges are not included, otherwise too many will only be discarded. It may be a good idea to add one or two pairs; ones chosen to compare the left and right halves, such as those from the Whitstable sample. Alternatively thin sections which were made twice, “re-makes” could be selected to see if these are noticed.

Observations Both blind tests were set up to assess how accurately seasonality, the age, and the provenance of the oyster could be determined. Being able to accurately assess the month of death for each oyster was obviously the most important aspect of the blind test as several archaeological assemblages were to be analysed in order to gain an overall view of the season/s of exploitation of oysters. Each slide was examined and an estimate of the month of death was made. Occasionally it was difficult to be absolutely sure about one month, especially around the time of annual line formation, which may occur in March or April. In cases such as this “March/April” was entered rather than just choosing one month. Sometimes a season was also noted, or a structural observation was made instead, such as “line forming” or “pre-line”. This simply indicated that the time of the year had been recognized, if the estimated month proved to be incorrect.

A good mix of slides from very difficult to fairly clear ones were chosen, with 17 from Southampton, 14 from Chelmsford, 13 from Truro and 6 from Whitstable. Of these, 3 pairs were chosen from Whitstable: W.1.2 left and right, W.1.15 left and right and W.1.23 left and right. A pair and re-make were also chosen from site J, Chelmsford: C.3.J.15 left, and right a and b.

62

BLIND TESTING

Sample C.3.A.12.A T.11.O.5.R S.7.B.6.L W.1.2.L T.8.O.10.R C.7.A.15.L S.10.F.6.L C.8.H.9.R W.1.15.L C.13.J.20.L T.2.W.10.L S.9.F.4.L C.8.E.17.L T.9.O.8.R S.10.H.9.R S.5.E.16.L W.1.2.R T.8.O.11.R T.7.R.7.L C.9.A.9.L S.10.B.11.R C.12.J.14.Rb W.1.15.R T.2.R.9.L S.3.I.19.R T.8.O.8.R C.7.H.11.L S.1.H.7.L T.10.R.11.L C.12.J.11.Ra T.4.W.12.L S.3.D.10.R C.3.J.15.Ra S.9.F.4.R S.12.F.10.R S.3.E.18.R W.1.23.R T.5.R.3.L S.10.L.6.R C.10.H.12.L S.13.C.14.L C.12.J.9.L T.12.R.11.L S.8.F.6.L C.13.E.9.L W.1.23.L T.5.V.6.R S.6.L.5.L C.3.J.15.Rb S.5.C.6.R

Run 1 May April/May August April/May September July December November March March May November Sept/Oct Dec/Jan May April October September November November February April May Dec/Jan October November Dec/Jan Nov/Dec May March March February April/May April August December March March May October March July July March June/July

Run2 April/May April/May August April October August March November April March April/May October October December October April April August November December February April May March Aug/Sept November December January February April March Feb/March April April September December March March April September March July June March May

Run 3 May March Aug/Sept April October Aug/Sept Nov/Dec October April March/April April Sept/Oct Sept/Oct Nov/Dec Nov/Dec March/April April September September December November February April May April August September December Oct/Nov February July March March September Feb/March May April August January December March March May September March July June March/April May

Date 13th May 17th March 28th July 19th April 1st October 17th September 25th November 14th October 19th April 5th March 23rd April 30th September 9th October 18th November 25th November 28th May 19th April 1st October 9th September 21st November 25th November 27th February 19th April 22nd April 4th March 1st October 11th September 4th December 2nd December 27th February 2nd June 4th March 22nd April 30th September 20th January 4th March 19th April 29th July 2nd December 10th December 24th March 27th February April 19th August 7th March 19th April 29th July 24th June 22nd April 28th May

Score 3 3 3 3 3 2 2 3 3 3 3 2 3 3 2 2 3 2 3 3 3 3 3 3 2 2 1 3 3 2 2 3 3 1 3 1 3 2 1 3 3 3 3 2 3 3 3 3 3

Table 6.1: Results from the 3 runs compared with the actual date of death and scoring system; 1 point for each estimate within a month of being correct. Estimates expressed as April/May score 1 point as long as the real date is between the 15th March and 14th June. Those months in bold type in “runs” columns refer to estimations which were incorrect by more than one month.

63

CHAPTER 6 The age of the oyster is also potentially significant. It is not necessary to know the age of the oyster when assessing seasonality but it is important to be able to assess age if comparing this with shell length. In many of the archaeological middens the oysters appear to decrease in size from the Mesolithic to the Neolithic. If this is due to unfavourable environmental changes the size in relation to age should decrease. If, however, oysters appear to be getting smaller through time an investigation into their ages may simply show that they are being harvested at a younger age. A problem with testing the identification of age is that none of the oysters in the control sample are of known age, except those from Whitstable but even these are known to be either 3 or 4 years old, rather than a precise age. The test therefore aimed to see whether the same number of annual lines could be identified in the three runs and how this compared to the original notes made.

Table 6.2 shows that overall, 91% of the readings made were correct or within a month of the true date of the death of the oyster. The success rate of the runs increase from 87% from the first run to 94% on the last run. This could either be explained by increasing familiarity with the test samples or the varying astuteness of the tester. Apart from the Whitstable pairs and site J examples which were recognized on the first run (see below) no conscious recognition of any slides or the seasonality of the oysters was made on the latter 2 runs. The periods in between tests were too long, the sample size was too large and the slides had been mixed and renumbered. However, if the conditions of runs 1, 2 and 3 are referred back to it can be seen that eye strain had presented a problem in the first two tests and it is felt that eye conditions, timing of the tests and work of the preceding weeks played a part in the varying levels of accuracy achieved. The scoring system is a statistical means of quantifying this data. There is, however, a problem with this in that categorizing the oysters into months means that they are being placed into purely arbitrary divisions, unless of course they had been collected in exactly the middle of each month. Those collected from Truro on the 1st October are really on the September October borderline. If T.8.O.8.R had been gathered one day earlier on the 30th of September the 3 estimates of “October, Aug/Sept, August” would have scored 3 points rather than 2. This is also true of S.9.F.4.L which had been collected on the 30th of September. If this had been collected one day later in October the estimates for this thin section would also have totalled 3, rather than 2.

Assessing the provenance of each oyster was simply carried out to see whether it was possible to recognize the different locations and it was hoped that in certain cases the individual sites would also be recognized. For each thin section, notes on seasonality, age and location or site were made. If for any reason the slide was chosen to be ‘discarded’ this was entered and the reason for its discard was also made. Any other comments were also noted, such as if the slide was particularly difficult to interpret and if there were any doubts as to the assessment entered. Transcripts of the 3 runs are in Appendix 2.

The twelve months in bold in Table 6.1 are those estimates which were not within a month of being correct. Of these twelve only 2 are several months out. The first is S.10.F.6.L on run 2 where the estimate is March and the actual date is 25th November. The second is S.3.I.19.R on run 1 where the estimate is Dec/Jan and the true date is 4th March. As mentioned in the last chapter, the November to March period is a particularly difficult season in which to make interpretations. The growth of the oyster slows down dramatically, a triangle has usually formed and the edge is dipping. There are very few indicators within this period as to the precise stage of pause in growth and the only method is to assess how much dipping has occurred and whether an annual line is just about to form.

Results Seasonality Table 6.1 presents the results from the three runs and the date when the oyster was actually collected. A scoring system was devised for assessing accuracy and this will be described below. The blank boxes represent those thin sections which were discarded because an assessment could not be made. It can be seen that the estimates in each run are in most cases very close to the real date of death. In an attempt to quantify this, a scoring system was devised to see how often the estimate was within a month of being correct. One point was awarded for each estimate made which was right, or within a month of being so (including double estimates such as April/May). Table 6.2 summarizes the data for each run, and the overall score.

discarded sample size correct % correct

Run 1 Run 2 5 5 45 45 39 42 87 93

Rather than assigning individual months, five or six seasons could be used focusing around the shells typical annual growth patterns. The first season would be at the period of line formation which may encompass the months March and April, occasionally May. The next season is post line formation when a line has just formed but there is still very little growth; April, May and June. Growth begins to accelerate after this, pre mid-line, the months being June and July. August, September, October and November can usually be identified as later summer, as a post mid-line period but here growth has not begun to slow down and the edge has not begun to dip. November, December, January and February, even March can be grouped together as recession where the

Run 3 Total 1 11 49 139 46 127 94 91

Table 6.2: Statistics for each run and the total, and calculations of correct assessments of seasonality for each run and overall. 64

BLIND TESTING Sample

Run 1

Run 2

Run 3

Notes

C.3.A.12.A T.11.O.5.R S.7.B.6.L W.1.2.L T.8.O.10.R C.7.A.15.L S.10.F.6.L C.8.H.9.R W.1.15.L C.13.J.20.L T.2.W.10.L S.9.F.4.L C.8.E.17.L T.9.O.8.R S.10.H.9.R S.5.E.16.L W.1.2.R T.8.O.11.R T.7.R.7.L C.9.A.9.L S.10.B.11.R C.12.J.14.Rb W.1.15.R T.2.R.9.L S.3.I.19.R T.8.O.8.R C.7.H.11.L S.1.H.7.L T.10.R.11.L C.12.J.11.Ra T.4.W.12.L S.3.D.10.R C.3.J.15.Ra S.9.F.4.R S.12.F.10.R S.3.E.18.R W.1.23.R T.5.R.3.L S.10.L.6.R C.10.H.12.L S.13.C.14.L C.12.J.9.L T.12.R.11.L S.8.F.6.L C.13.E.9.L W.1.23.L T.5.U.6.R S.6.L.5.L C.3.J.15.Rb S.5.C.6.R

4 4? 2? ? 4 3 4 5 8? 5 4 5? 4? 4 or 5 3 4 4 3? 4 3 2 3? 7 or 8 3 2 4 2 or 3 2 or 3 1 ? 4 4 7? ? 3 or 4 4 3 2 3? 4? 2 4 4 2 3 ? 3 3? 7? 3

4 3 2 2 4? 3 5 5 6 or 7 4? 3 or 4 4 or 5 4 4 3 ? 4 3 4 3 2 3 or 4 6 3 3 or 4 5 3 2 2 ? ? 4 ? ? 3 4 3 4? 4 or 5 4 3 or 4 4? 5? 2 3 ? 3 ? ? 3

4 4? 2 3 3 3 or 4 5? 4 4? 3 3 or 4 3? 4or 5 3 3 3 3 ? 4 3 2 4 3? 2 or 3 2 or 3 3? 3? 2 2 ? 2 3 ? 3 or 4 2 4 4 3 3 4 2 or 3 6 3 3 or 4 3 or 4 ? 3? 3 4 or 5 4?

4 4 1 2 3? 3 4 4 4 or 5 2? 2 5? 3 2 3 2 2 1 or 2 4 3 2 3? 4 or 5 2 2 2? 2 or 3 2 1 3? 2 4 ? 6? 3 1 3 or 4 2 2 3 2 3 3 2 3 ? 3? 2? 4 or 5 2 or 3

edge is dipping but usually late winter, i.e. March can be recognized as pre-line. These kinds of observations were often made when making the original notes and diagrams (see Appendix 1) and when doing the tests (see Appendix 2).

Age An annual line does not represent the time of birth of the oyster. The oyster is ejected into the sea in the early summer and will be settled and start to grow before the autumn. The first annual line is formed in the spring, and this first line was noted by Richardson et al. (1993) as hard to discern, usually being a series of fine lines. The annual lines therefore simply mark the annual event of the oyster’s growth after a winter cessation, and it may be used as an indicator as to how many springs the oyster has lived through. The first annual line, or series of fine lines was rarely counted in this analysis because they were hard to identify, or occasionally the hinge had broken at the tip and this line was lost. Table 6.3 presents the age estimates from each of the 3 runs and compares this with the age estimates made in the original notes. The rows highlighted in bold indicate those samples for which the estimates were fairly constant. The table shows that when comparing ages between runs there is a lower level of agreement than there is with seasonality assessments. There is no point using a scoring system here as the actual ages of the oysters are not known, except those from Whitstable which are meant to be 3 or 4 years old. There are three major problems when counting annual lines. The first is that if there looks to be a line forming on the edge deliberation will arise as to whether this is counted or not. On some occasions it will be and some it will not. Secondly, on some occasions mid-lines look very much like annual lines and they may be counted. Thirdly, the first line formed is usually very unclear and when the original notes were being made any possible first annual lines tended to be ignored because they did not conform to the classic characteristics of an annual line. This is why the age counts in the right column “notes” are often smaller than those counted in the runs. There are some examples here that are obviously very clear and there is little disagreement between runs and notes (those in bold print). There are others however, which have vastly different counts. W.1.15.L for instance has a count of “8?” in Run 1, “6 or 7” in Run 2, “4?” in Run 3 and “4 or 5” in the notes. This is a Whitstable oyster so it should only have 3 or 4 lines, therefore it is probable that mid-lines were being counted. There does, however, appear to be similar numbers of unclear readings from Southampton, Truro, Whitstable and Chelmsford.

Table 6.3: The age estimates from each of the three runs in comparison to the original estimates made in the notes. Those examples in bold have a higher degree of agreement between runs and notes. 65

CHAPTER 6 Sample C.3.A.12.A T.11.O.5.R S.7.B.6.L W.1.2.L T.8.O.10.R C.7.A.15.L S.10.F.6.L C.8.H.9.R W.1.15.L C.13.J.20.L T.2.W.10.L S.9.F.4.L C.8.E.17.L T.9.O.8.R S.10.H.9.R S.5.E.16.L W.1.2.R T.8.O.11.R T.7.R.7.L C.9.A.9.L S.10.B.11.R C.12.J.14.Rb W.1.15.R T.2.R.9.L S.3.I.19.R T.8.O.8.R C.7.H.11.L S.1.H.7.L T.10.R.11.L C.12.J.11.Ra T.4.W.12.L S.3.D.10.R C.3.J.15.Ra S.9.F.4.R S.12.F.10.R S.3.E.18.R W.1.23.R T.5.R.3.L S.10.L.6.R C.10.H.12.L S.13.C.14.L C.12.J.9.L T.12.R.11.L S.8.F.6.L C.13.E.9.L W.1.23.L T.5.U.6.R S.6.L.5.L C.3.J.15.Rb S.5.C.6.R

Run 1 C

W C S C

Run 2 C, site A S W S or T C S W

C T S C S?

W

C S C W T S T or S C

C

S or T W T C S W T S or T

S C, site J T S C, site J

C, site J T

S? S or C W T S C S C T or S

S C W T

C, site J

C, site A? S C S? S

C S??? S C, site J T or S

T T C, site J S

Run 3 C, site A T S W T? C S C W C T C S or T S? S W T? T? C S C? W T S T S S? C, site J T S C, site J S S C W S T or S C S C S S S? T S C, site J S

Score 3 1 2 3 2 2 3 2 2 2 2 1 3 1 1 2 3 2 1 3 3 2 3 3 3 2 1 2

Location Table 6.4 presents the estimates made on the provenance of each oyster and again a scoring system was used to see what percentage of correct interpretations were made. When possible, an assessment of site was also made but this has not been scored. Only 33 times in the 3 runs no attempt was made at estimating location. Of the remaining 117 slides the correct assessment was made 106 times, that is a 91% success rate. Any confusion tended to arise between oysters from Truro and Southampton where disturbance or unclear samples sometimes looked similar. Occasionally the individual sites were recognized. Site A, Chelmsford was particularly identifiable because the annual lines are very clear and there is very little disturbance in oysters from this site. On one occasion however, a shell from the Chelmsford site H (C.10.H.12.L) was wrongly identified as site A. Site J at Chelmsford was also immediately recognized for the large amounts of disturbance. The fact that the left and right and re-make of a shell from this site had been included in the sample was also noticed. In run 1 the Whitstable pair W.1.15 left and right was recognized and a tentative pairing was made between W.1.2 left and right. The last Whitstable pair W.1.23 left and right was not noticed in any of the three runs.

3 3 2 3 1 3 1 3 2 2 3 3 3 1 2 1

Blind Test 2 An instruction sheet was devised for beginners to use in order to teach themselves the means of assessing seasonality from thin sections of oysters. These instructions are merely a version of chapter 5. Firstly, using named examples from the control sample, it was shown how annual lines could be recognized and how these could be identified against disturbance lines. The different characteristics of annual lines from the four locations were demonstrated and it was also described how they may look different from site to site. Secondly it was shown how annual lines may be anchored to a particular time in the year by looking through shells collected in the spring months of March, April and May to see the lines forming on the edge. Thirdly the variability of growth through the year and ways of interpreting a particular month or season was presented. Identifying features were explained, as well as the problems involved with measuring amounts of growth from the last annual lines. Finally the novice was encouraged to take time to go through the control sample collection using the sketches and notes as a self teaching exercise, on the basis that experience and practice would be needed. I was not present for the week that this self teaching was being done so no help could be given.

2 2 3 3

Table 6.4: Locations and sites which were identified in runs 1-3 and scoring system.

66

BLIND TESTING The novice accomplished this exercise in three time slots, totalling about five hours. In this time the instruction sheet and examples was completed but the self teaching in order to build up experience was not pursued. Measurements were not used at all. Three main points were made by the novice: •

• •

achieved, but to gain better results a greater amount of time input would have to be made. It would be recommended that the whole control sample should be analysed and notes and sketches made. Larger blind tests should also be conducted and until an 80 to 90 % success rate had been achieved application to archaeological samples should not be made.

Initially it was felt that whilst individual examples were clear, problems arose when comparing annual lines from the different locations. For example, having looked at one slide to identify the annual lines, the next group of examples contained, for instance, a greater number of disturbance lines and all sense of what annual lines were in these examples would be lost. Secondly it was felt that the notes and sketches I had made had helped but they were really geared for my purposes and not for the novice. Thirdly it was acknowledged that if the skill was being learnt properly, a more rigorous study of the examples with greater time investment and drawing of sections would have been made.

Age Table 6.6 presents the results achieved by the novice when aging the oysters, as compared with the 3 runs made on Test 2 and the estimations made in the initial notes. Once again it was felt that a scoring system could not be carried out because real ages were not known. In comparison to the age estimates made in the first 3 runs of test 1, the results of the novice err on the low side. It is possible that the first couple of lines were not being identified and from the sketches accompanying the notes made by the novice it seemed that only the annual lines near to the growing edge were being picked up. Generally the earlier annual lines are not so clear and tend to be further apart.

The first 20 slides of run 3 were used in this blind test, although the first slide was not attempted because it was broken accidentally during testing. The sample size was therefore 19. Seasonality and age were assessed but no attempt at guessing the site was made. Notes and sketches were made for each sample and the notes have been tabulated and included in Appendix 2.

Summary The fact that in 91% of assessments the month of death was correctly made, and that in 91% of cases the location, and occasionally site, were also recognized shows a high level of familiarity with the samples. Three out of the four pairs and the re-make were also spotted. This type of familiarity and confidence is essential before looking at the archaeological samples. Making an assessment of the age of the oyster is clearly more problematic and although estimates can be made, caution must be taken if attempts are to be made in trying to compare age against shell size. If age analysis is to be attempted on the archaeological shells two rules should be followed regarding consistency. Firstly, as long as the hinge is complete the first line should be searched for and counted. Secondly if an annual line can be seen on the edge it too should be counted every time. In this way results will at least be comparable.

Seasonality Table 6.5 presents the results of assessing month of death by the novice against the same samples from the 3 runs of test 1. The scores of both tests may also be compared. Of the 19 samples 4 were discarded. Using the same scoring system as in Blind test 1 the number of correct scores was 8. This gives a 53% rate of successfully assessing the month of death. This may seem a low percentage but if the estimates are looked at again, and seasons, outlined in test 1, are used there are only actually 3 occasions when estimates are grossly wrong. S.10.H.9.R (June/July instead of November), and C.9.A.9.L (July instead of November) are both about 6 months out and S.3.I.19.R is given the post line month of June, instead of the pre-line month of March. In the initial notes made (see Appendix 1) S.10.H.9.R is acknowledged as not having much growth for a November specimen and estimates could well be made as earlier. For C.9.A.9.L, however, it is noted that an annual line may almost be mistaken at the edge although there is not enough dipping, implying that if anything, this shell may be interpreted as slightly later than November rather than earlier. For S.3.I.19.R a small triangle has formed in the ligostracum which should indicate that the month of death is at least November.

The Blind Test 2 revealed that a larger time investment than five hours is needed to be confident in assessing seasonality. It is recommended that the whole sample should be analysed and blind tests similar to these outlined in this chapter should be conducted until an 80-90 % success rate is achieved. If locations and sites can also be recognized this simply reinforces the fact that an understanding of annual lines and oyster growth has been achieved.

These results are only based on a five hour self teaching exercise and it is felt that a degree of understanding had been

67

CHAPTER 6 Sample S.10.F.6.L C.8.H.9.R C.13.J.20.L T.9.O.8.R S.10.H.9.R W.1.2.R C.9.A.9.L W.1.15.R S.3.I.19.R T.8.O.8.R C.7.H.11.L T.10.R.11.L T.4.W.12.L S.9.F.4.R S.12.F.10.R S.3.E.18.R T.5.R.3.L T.12.R.11.L W.1.23.L

Run 1 December November March Dec/Jan April November April Dec/Jan October November Nov/Dec May February April/May August May -

Run 2

Run 3

Date

My Score

March Nov/Dec 25th November November October 14th October March March/April 5th March December Nov/Dec 18th November October Nov/Dec 25th November April April 19th April November December 21st November April April 19th April March April 4th March Aug/Sept August 1st October November September 11th September January Oct/Nov 2nd December July 2nd June September 30th September Feb/March Feb/March 20th January April May 4th March September August 29th July April May April 19th April

2 3 3 3 2 3 3 3 2 2 1 3 2 1 3 2 2 3

Test 2 Novice Score Novice Sept/Nov 1 March/April 1 Jan/Feb June/July April/May 1 July line formed 1 June July December Aug/Sept 1 Dec/Jan 1 December Aug/Sept 1 April 1 -

Table 6.5: Assessments of months made by the novice against those of 3 runs in Blind test 1.

Sample

Run 1

Run 2

Run 3

Notes

Novice

S.10.F.6.L C.8.H.9.R C.13.J.20.L T.9.O.8.R S.10.H.9.R W.1.2.R C.9.A.9.L W.1.15.R S.3.I.19.R T.8.O.8.R C.7.H.11.L T.10.R.11.L T.4.W.12.L S.9.F.4.R S.12.F.10.R S.3.E.18.R T.5.R.3.L T.12.R.11.L W.1.23.L

4 5 5 4 or 5 3 4 3 7 or 8 2 4 2 or 3 1 4 ? 3 or 4 4 2 4 ?

5 5 4? 4 3 4 3 6 3 or 4 5 3 2 ? ? 3 4 4? 5? ?

5? 4 3 3 3 3 3 3? 2 or 3 3? 3? 2 2 3 or 4 2 4 3 3 ?

4 4 2? 2 3 2 3 4 or 5 2 2? 2 or 3 1 2 6? 3 1 2 3 ?

? 5 4 2 2 1 1 5 2 3 ? ? ? 4 3 2 2 2 ?

Table 6.6: Results of age estimates from Blind test 1 and notes in comparison with estimates made by the novice.

68

CHAPTER 7

Archaeological Sites and Sampling Once the method for making and examining thin sections had been developed and interpretation validated through blind testing, it was possible to apply the same techniques to a sample of archaeological oysters. Initially, only the site of Norsminde was to be sampled. This site had been excavated in the 1970s and at this time a cubic metre of material had been removed and taken to Cambridge for further research. This cubic metre spanned the Mesolithic and Neolithic periods and would allow for a seasonality assessment over time. However, it was felt that it would be informative to look at other sites as well and with the generous help of Søren H Andersen (The National Museum of Denmark) five other sites were sampled. There are many problems with sampling oysters from a midden, for if oysters are sampled from one discreet area they are only going to represent the seasonality for a small moment in time and not necessarily the seasonality for oysters in the surrounding area or for the midden as a whole. It is therefore preferable if samples are taken from different areas and if the excavation procedure provides an understanding of how the midden built up through time, and also how formation processes have affected the midden. Two of the other sites sampled, Visborg and Dyngby (Andersen 2000, 2001), were under excavation and were visited in the summer of 1997. Here samples were taken from different areas of the excavation in order to investigate spatial variation. The other three sites were random samples of shells from the archives of three previously excavated sites, Havnø (Madsen et al 1900), Lystrup (Andersen 1996, 2001) and Eskelund. The location of the six midden sites under investigation can be seen on figure 7.1. In other studies like this one, sample sizes can vary significantly with totals falling anywhere between twenty and several hundred shells. Very often, however, there is little discussion as to where in the midden they were excavated from, presumably because the general assumption is that they were always procured at only one time in the year. Sample sizes in this study, with the exception of Visborg and Dyngby, tended to depend on the number of shells which were available at the time, as well as how many thin sections could be reasonably made. It was considered that a sample size of approximately 300 thin sections would perhaps be sufficient to learn something of season of death of oysters from archaeological sites. The sampling procedure was largely seen as experimental and it was hoped that some conclusion would be formed as to better ways of sampling from a midden. This chapter will describe the six sites and outline how the samples were taken, catalogued and how they were then sub sampled for thin sectioning.

CHAPTER 7

30 km

NORTH SEA

KATTEGAT Visborg

Havnø

Lystrup

JUTLAND Eskelund Norsminde

Dyngby

Figure 7.1: Map of northern Jutland showing the location of the six sites and the Mesolithic coastline. Darker area of the sea denotes present day land. The midden at Norsminde is roughly oval in outline, about 30 metres long, about 5-12 metres wide and up to 1.5 metres thick, being wider and thicker at the east end, figure 7.2 (Andersen 1991). The deposit appears to have accumulated from west to east and then built up vertically at the east end, presumably because of the natural boundary of the slope which would also account for it being thicker here. There are Mesolithic and Neolithic layers in this midden, of typical composition as described in chapter 1. The Mesolithic layers are dominated by the oyster and the Neolithic layers by the cockle, but other faunal and cultural remains were found.

Norsminde Norsminde was discovered in 1972 following a series of intensive reconnaissances along the Norsminde fjord. The site was totally excavated by Søren H Andersen from 1972-1989 (Andersen 1976; 1991). Much of the fjord today is reclaimed land. The mouth in the Atlantic period would have been about 500 metres wide but has gradually been closed off by sand banks and beach ridges. The area in front of the midden would have sloped down gradually to the sea and a natural shell-bank is thought to have existed here in the mouth of the fjord. The midden was built up on glacial clay on an old beach cliff and sits in a natural recess in the slope, the east end abutting a steep part of the slope. This is not the only shell midden in the fjord. There is also the large site of Flynderhage and the site of Norslund.

Seasonality studies have been performed on the fauna from Norsminde and in general it would seem that resources were being exploited throughout the year. Although some cockles and otoliths were examined by Froom (1979) by more recent standards these methods are fairly crude and no modern controls were used, making the accuracy of the results

70

ARCHAEOLOGICAL SITES AND SAMPLING

X

Figure 7.2: Plan of the Norsminde excavations (Source: Andersen 1991). X marks the square from which the column sample was excavated.

table 7.1 and the interpretation was that fishing took place mainly in the summer half of the year. Some of the fish caught in winter may in fact be autumn or spring catches but equally they may be winter (Enghoff 1994).

questionable. The seasonality of cockles was assessed by visually estimating the distance from the last annual ring to the lip of the shell. Otoliths of cod were also analysed looking at the opaque and hyaline zones which indicate February to October, and November to January respectively. It was concluded that cod was exploited in the spring and summer and shellfish were gathered throughout the year but predominantly in the spring.

Species Winter/spring Cod Saithe Flounder 1 Plaice Total 1

Spring 46 6

52

Summer 49 13 36 2 100

Autumn 12 4 15

Winter 25 3 4

31

32

Table 7.1. Source: Enghoff (1994, 81). The distribution of otolith readings from Norsminde.

The fish remains have since been studied by Enghoff (1991). Cod and flatfish were the predominant species. It is thought that the fishing took place in the summer season because cod are easier to catch at this time when they frequent coastal waters. The presence of mackerel which is a migratory fish, found in these waters in the summer, supports this hypothesis. Otoliths from the site were also analysed by sectioning. A total of 216 were studied by E. Steffensen (The Danish Institute of Fisheries and Marine Research). The results are presented in

Bone counts for each species were not given in the preliminary report but from the presence of the fur-bearing animals, beaver, wild cat and wolf, and the migratory duck and swan, it was implied that there was evidence for winter occupation. An overall seasonality assessment for the Mesolithic was made:

71

CHAPTER 7 “it is possible to state that summer, autumn and winter indicators were found, but it would be premature to argue for a permanent year round occupation.” (Andersen 1991, 37).

for each of the levels 1-7. Although layer 7 was considered a Mesolithic layer the 10 cm spit below layer 5 was divided into layers 6 and 7 and therefore there was less material in these layers, and less shells which could be sampled. In the Mesolithic layers there were obviously many more oyster shells but only those which were not broken were selected and this amounted to roughly 25 for each of layers 8-10. The total number of shells sampled for cataloguing was 163.

The Ertebølle midden was built up of local shell heaps growing both horizontally and vertically, especially in the eastern area and can be divided into at least three fairly well defined areas centred around associated fireplaces. The Neolithic layers are situated directly upon the Ertebølle horizon with no apparent layer in between although there is mention of “a few indicators of a sterile layer of erosional level at the top of the Ertebølle midden” and it is stated that it is impossible to prove that there was no hiatus between the Ertebølle and TBK occupation. Again the midden has been divided into about three areas and in the east area there are 5-6 well defined layers, possibly representing occupational episodes (Andersen 1991).

Visborg At the time of this research Visborg had been under excavation by Søren H Andersen for 3 years. Approximately 20 m² were opened in 1997. The site is situated on the north side of the Mariager fjord. It was on the edge of the shoreline, although since the Mesolithic period the fjord has narrowed and there is reclaimed land in front of the site. It is the largest known midden in Denmark being roughly 600 metres long and about 30 metres wide. Much of the midden is ploughed away and only the deepest 20-30 cm are still preserved. The shells on the surface of the midden are fairly crushed probably due to trampling by the Ertebølle people, a minor transgression of the sea after habitation and modern plough damage. It is mainly composed of oyster shell although of course other faunal and cultural remains have been found.

Thirty-three C-14 samples were taken from Norsminde. Twenty six were taken from oysters, five from cockles and one from bone (the dates given below have been taken from Andersen 1991 and calibrated to 95.4 % confidence using Oxcal V2.18, Radiocarbon and Statistical Analysis Program, Christopher Brock Ramsey 1995). The oldest part of the Ertebølle midden is dated to 4900-4350 cal. BC (K-2187, 3820±100 b.c.). All the other dates, however, are concentrated in the period 3500-3100 b.c and the next oldest date is 45204040 cal. BC (K-2447, 3520±100 b.c.). The top horizon of the Ertebølle midden is dated to 4040-3640 cal. BC (K-2663, 3090±90 b.c.). These dates and the artefact inventory associated with these layers are indicative of the late Mesolithic Ertebølle culture. The ten C-14 dates from the main part of the TBK midden date this part of the midden to around 3990-3610 cal. BC (K-2192, 3010±100 b.c.) with the exception of a younger and probably individual occupational episode at the most eastern part of the midden where two dates of 3650-3000 cal. BC (K-2664 2650±85 b.c.) and 3370-2920 cal. BC (K-2665, 2530±85 b.c.) came from.

The midden is older in the centre and appears to have accumulated along the coast both to the west and the east. Figure 7.3 shows the extent of the midden and the radiocarbon sample points (the dates have been calibrated to 95.4 % confidence using Oxcal V2.18, Radiocarbon and Statistical Analysis Program, Christopher Brock Ramsey 1995). The dates from west to east are: (A) 3750-3700 cal. BC (K-6553, 3150±70 b.c.), (B) 4790-4460 cal. BC (K-6552, 3820±75 b.c.), (C) 4700-4000 cal. BC (K-6419, 3590±105 b.c.), (D) 46704330 cal. BC (K-6418, 3640±75 b.c.), and (E) 4250-3600 cal. BC (K-6417, 3120±100 b.c.), the latter being the area from which the oysters were sampled. Although oysters predominated in this area, this part of the midden has been attributed to the early TRB culture.

In 1977 one cubic metre of material was excavated by Peter Rowley-Conwy and Marsha Levine and taken to Cambridge. This column sample of midden was removed in 10cm spits, levels 1-6 from the Neolithic midden and 7-10 from the Mesolithic midden. The location of the sample is indicated in figure 7.2. The material from each spit was water sieved through 2mm and 1mm sieves, dried and placed into bags to be sorted (Froom 1979). Although the layers were only arbitrary spits there was evidence during the excavation for a chronological sequence from bottom to top of the midden. It was therefore decided that oysters would be sampled from each layer to see if there were any changes in exploitation practices through time.

Although the material from Norsminde was useful in adding a chronological dimension to the seasonality study there was to be no spatial analysis. At Visborg it is understood that material appeared to accumulate both horizontally and vertically and it seems that the midden can be separated into discrete areas of accumulation. In the area that had been opened in 1997 there appeared to be 2 mounded areas of material, figure 7.4. A study between the two areas were therefore made. As there appeared to be some horizontal deposition also and the shells appeared to be smaller nearer the top of the midden, samples were taken from the top and bottom of the sections.

A sample was to be taken from every layer but because there were more Neolithic layers, and because initially it was mainly the Ertebølle material that was of interest a larger number of shells were taken from each Mesolithic layer. Complete upper valves were selected where possible and those with broken hinge areas were not chosen. In each Neolithic layer there were only ever about 14 shells at the most which satisfied these criteria. Therefore, around 12 or so shells were sampled

Samples were taken from 5 points. Samples 1 (3933 OXA) and 2 (3933 OXC) were taken from an exposed section, sample 1 from the base and sample 2 from the top of the section, about 30 cm apart, figure 7.5. Samples 3 (3933 OXH) and 4 (3933 OXJ) were taken from the bottom and top of another section, which appeared to represent a different 72

ARCHAEOLOGICAL SITES AND SAMPLING

Figure 7.3: Plan of the midden at Visborg (Source: Søren H Andersen). Letters A-E represent the points where radiocarbon samples were taken. The box indicates the area excavated in 1997.

Figure 7.4: The 1997 excavations at Visborg. The photograph looks east. The two areas of accumulation are roughly separated by the section through the middle of the excavations. 73

CHAPTER 7 accumulation of mound material, figure 7.6. The shells from the lower point seemed to be more complete whereas those from the top were more fragmentary. The oysters near the base of the section were also intermixed with a fairly high proportion of mussels, although this lens of mussels was not particularly extensive and could hardly be traced in the opposite side of the one metre trench. The oyster shells were carefully removed from the sections by hand and it was possible to obtain between 10 and 15 complete hinges in close proximity to each other. Any more and the sample would have been fairly spread out and the difference between the upper and lower points less distinguishable. A random sample was also taken from the spoil heaps on the east of the midden. This consisted of a carefully collected sample of 15 complete right valves with hinges intact. Altogether, the sample size for this site was 65 shells with complete hinges.

Dyngby Dyngby lies on the north side of a reclaimed bay about 2 km long and 1 km wide. It was found during a reconnaissance of the bay and was under excavation by Søren H Andersen at the time of this research. It is a very small midden in comparison with Norsminde and Visborg, its dimensions being only about 12 metres east-west and 10 metres north-south, with a maximum depth of about 30 cm. It is mainly composed of fairly small oysters with some other faunal remains present. The flint assemblage is quite specialised with a predominance of axes. So far there is only one radiocarbon date for this site of 5190-5070 cal. BC (Søren H Andersen pers. comm. 1998). The material at Dyngby was interesting in that the oysters were very small and became even smaller at the top of the midden. This suggests some chronological patterning and accumulation is thought to have occurred vertically. A spatial and chronological sampling methodology was again used. Two sample points were chosen. Sample 1 (3954 DAJ) was taken from a section in the centre of the midden, figure 7.7. A total of 19 shells were removed carefully from an area 60cms long and a maximum of 15 cm in depth. Samples 2 (3954 DAV) and 3 (3954 DAW) were taken roughly 30 cm apart from the bottom and top of an exposed section, figure 7.8. There appeared to be more cockles in this section than the area from where sample 1 was taken. Nearer the top of the section there were less cockles but some mussels. The shells of sample 2 were larger but only 14 were sampled from this area. At the top of the section the shells were so much smaller, only appearing to be about 1 or 2 years old and therefore more were taken because it was thought there may be problems with thin sectioning them. A random sample of 36 shells was also gathered from the spoil heaps by Søren H Andersen. The total number of shells sampled was 93.

2

1

Figure 7.5: the Visborg section where samples 1 (3933 OXA) and 2 (3933 OXC) were taken from. Sample 1 from the base and sample 2 from the top of the section, about 30 cm apart.

4

3

1

Figure 7.6: the Visborg section where samples 3 (3933 OXH) and 4 (3933 OXJ) were taken from. Sample 3 from the bottom and sample 4 from the top of the section.

Figure 7.7: Sample 1 (3954 DAJ) was taken from this section at Dyngby. The photograph was taken before sampling

74

ARCHAEOLOGICAL SITES AND SAMPLING from Eskelund, 18 from Havnø and 19 from Lystrup were selected.

Cataloguing and Sub-Sampling 3

Cataloguing For each of the 6 sites the shells were catalogued. The cataloguing involved taking measurements of the hinge and length of shell, where possible and noting any features such as mineral staining. Although the samples obviously represent oysters gathered from different periods in time a plot of hinge length to shell length was made to demonstrate the differences in sizes between the sites, which had been noted in the field and when handling the shells, see figure 7.9.

2

Figure 7.8: Dyngby. Samples 2 (3954 DAV) and 3 (3954 DAW) were taken from the bottom and top of this section.

The shells from Visborg are clearly fairly large and are comparable with those from Chelmsford. Those from Havnø also fall in this size range which is not suprising with them coming from the same fjord. The shells from Lystrup are also similar. Those from Norsminde and Eskelund are on the whole slightly smaller but it is demonstrated very well here just how small those from Dyngby are. There is obviously a difference in oyster sizes and hinge lengths from site to site but this may simply be a product of micro-environments around the coast. It is shown in chapter 3 that shells from the modern control samples at the Chelmsford sites grow much larger than those on the south coast of England due to more favourable conditions (temperature, food, salinity etc.). In the case of Denmark, those oysters further south would have experienced low salinities as the salt water only enters the Baltic from the Kattegat in the North.

Havnø, Eskelund and Lystrup To add to the inter-site comparative work, the three sites of Lystrup, Havnø and Eskelund were randomly sampled. Havnø was investigated in the 19th century by the 2nd kitchenmidden committee and published in the volume by Madsen et al. (1900). The midden was about 100m long. A 23m by 2m trench was put through it, with two smaller 1m sections also taken at right angles to this larger trench. A hearth was found, along with flint, bones, and pottery. The midden is in the same fjord as Visborg but is thought to date slightly earlier, to the later Ertebølle period. There is also an Early Neolithic layer on top of the Late Mesolithic (Søren H Andersen pers. comm. 1998).

The colour of the shell and external characteristics were difficult to assess for although some colour could be seen when the shell was wet it was not as vivid as the control samples and many had leached to white. There tended to be some streaks of orange or purple or brown occasionally. Many of the various external characteristics had probably eroded away but there was sometimes evidence of worms from all of the sites, although not in large quantities. The only real distinguishing factors between sites was therefore the size and the condition of the shell due to taphonomic processes. The shells from Dyngby tended to be stained with iron oxides as did some from Lystrup, and these were also extremely fragmentary, due to their greater age.

Eskelund was partially excavated by Søren H Andersen and staff of the Forhistorisk Museum at different occasions during the last 20 years. It is unpublished. It is situated on the western outskirts of the city of Århus at Brabrand Sø, a prehistoric fjord and it lies at the west end of a small island. The site itself is about 50m long, 25m wide and about 10-25 cm thick. It is dated to the Late Ertebølle, about 3970 cal. BC (Søren H Andersen pers. comm. 1998). Lystrup is the oldest site of the six. It dates to the transition from the Kongemose to the Ertebølle. Four radiocarbon dates were taken from an oyster shell (5220-4940 BC), two pieces of hazel wood (5260-5000 BC and 5250-4960 BC) and a nutshell (5310-5080 BC) and further dating was taken from canoes found, 5570-5340 BC (Andersen 1996). It was excavated from 1980 to 2000 by amateur archaeologists under the supervision of Søren H Andersen. The site has not yet been fully published, although a report on the Ertebølle canoes has been made (Andersen 1996), as has an analysis of the fish bones found here (Enghoff 1994). The shell midden at Lystrup was about 100m long, 10 m wide and about 10cms in thick.

Sub-Sampling for Thin Sectioning Some of the shells were found to be too broken or fragmentary and could not be sectioned, therefore a sub-sample was selected. Sometimes during the thin sectioning process some of these shells broke or slides were made badly and these specimens were therefore discarded. Furthermore, inspection under the microscope sometimes revealed breakage along the growing edge of the shell which hindered interpretation and these too had to be discarded. N = the final sample size for the individual layers, samples and sites which were interpreted successfully. This number was very small at some sites due to the fragmentary nature of the shells. A summary of these sample sizes have been tabulated below.

From these 3 sites oysters were randomly selected from the archives by Søren H Andersen. Boxes of about 30 oysters from each site were sent to me. These were sorted and shells which had complete hinges were sampled. A total of 27 shells

75

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120

100

shell length (mm)

80

60 Havno Visborg Dyngby Norsminde Eskelund Lystrup

40

20

0 0

2

4

6

8

10

12

14

16

18

hinge length (mm)

Figure 7.9: Graph to show plots of hinge length to shell length for each oyster sampled from each site.

Norsminde Because the Norsminde material was the largest body of material it was decided that 130 shells should be thin sectioned from this site alone. Initially 10 shells from each Neolithic layer and 20 shells from the Mesolithic layers were to be subsampled. Those shells which did not have skew hinges were sectioned first, and if these broke on sectioning new ones were chosen. It was found that these shells were not particularly fragmentary but they did tend to split along growth lines if they were not sectioned extremely slowly, and in the end all the shells which had been catalogued were sectioned. The column “selected” on table 7.2 shows the final number which were sectioned successfully (93% of the 130 originally aimed for). The column “discarded” shows the number of shells which were later lost through the thin sectioning process or discarded during interpretation. The final number of slides which were made and interpreted successfully was 96, that is 79% of the selected sample.

Layer Catalogued 13 1 12 2 12 3 11 4 12 5 14 6 14 7 26 8 24 9 25 10 Sum 163

Selected 8 11 10 10 11 10 10 18 18 15 121

Discarded 2 3 2 1 3 3 1 3 4 3 25

N 6 8 8 9 8 7 9 15 14 12 96

Table 7.2: Table to show the numbers of shells catalogued, selected, discarded and finally the total number of interpretable thin sections for each layer at Norsminde.

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ARCHAEOLOGICAL SITES AND SAMPLING

Visborg

The shells from Eskelund and Havnø were in fairly good condition. Most of those from Havnø were sectioned successfully (94%) and a complete sample of 20 was selected for Eskelund, see table 7.5. Of these selected shells 75% from Eskelund and 76% from Havnø were interpreted successfully. Those from Lystrup, however, were very fragmentary and powdery probably due to age and on many there was iron oxide precipitate. Under the microscope they appeared to be tinged with orange, especially along incremental lines. This resembled the state of the shells from Dyngby, therefore it is extremely likely that Lystrup was also waterlogged at some stage in its existence. It also appeared that the conchiolin matrix which holds the calcium carbonate and aragonite together has probably been destroyed as most of the shells split very easily even with careful sectioning, and sometimes even before. Consequently, although 13 shells were thin sectioned (68% of the original sample) only 4 slides (31%) could be analysed, and these interpretations were only tentative.

All the shells sampled from Visborg were catalogued and then they were sub-sampled. The aim was to have 10 valves from each point, the total sample size for this site to be 50, but those which had very skew hinges or those which broke along the growth planes were not used. The actual numbers are shown in the “selected” column of table 7.3 (94% of the 50 aimed for). Again some were later lost in the thin sectioning process or could not be interpreted but in general the shells from this site were in good condition and of the 47 selected 38 were sectioned and interpreted, that is 81%. Samples 1 2 3 4 random Sum

Catalogued 14 13 11 12 15 65

Selected 9 10 10 8 10 47

Discarded N 3 6 2 8 1 9 3 5 0 10 9 38

Table 7.3: Table to show the numbers of shells catalogued, selected, discarded and finally the total number of interpretable thin sections for each sample at Visborg.

Site Catalogued 18 Havnø 27 Eskelund 19 Lystrup

Dyngby

Table 7.5: Table to show the numbers of shells catalogued, selected, discarded and finally the total number of completed thin sections for the three sites of Havnø, Eskelund and Lystrup.

Not only were many of the shells from Dyngby small but the site was fairly waterlogged and as a consequence many of the shells were very fragile and often stained with iron oxides. The size and delicate nature meant they were much harder to thin section. The aim was to get 10 good samples, preferably of the larger shells of at least 2 years from each sampling point (a total of 40) but this could not always be achieved, except with the random sample, see table 7.4. A total of 33 were sectioned, that is 35% of the original sample. Several were lost in the thin sectioning process or discarded during interpretation and only 21 thin sections could be analysed, that is 64% of the selection. Samples 1 2 3 random Sum

Catalogued 19 14 24 36 93

Selected 9 7 7 10 33

Selected 17 20 13

Discarded N 4 13 5 15 9 4

Summary of Sampling An analysis of the process from initial sampling through to final interpretation and the percentages of shells which were interpretable shows that on average about 20-25% of the sample will be discarded at some point. If the shells are initially in bad condition, broken and fragmentary as at Dyngby and Lystrup an even smaller interpretable sample is likely. This should be taken into account when sampling in the future to avoid ending up with sub-samples which are too small.

Discarded N 1 8 1 6 4 3 6 4 12 21

There follows the question of how large or small the final interpretable sample should be. Clearly the answer is the larger the better and it would seem that 10 interpretable thin sections from one sampling area should be a minimum requirement. The randomly sampled site of Lystrup did not fulfil these criteria and this sample along with those of Eskelund and Havnø should perhaps have been as large as 20. The sample sizes for the Norsminde material seemed satisfactory but again it would be interesting to see how much the interpretations would change if the sample sizes for each point at Visborg and Dyngby had been larger. The total sample sizes for the sites were 38 and 21 respectively, but the sizes from the individual sampling points are perhaps too small to make confident comparisons with each other.

Table 7.4: Table to show the numbers of shells catalogued, selected, discarded and finally the total number of interpretable thin sections for each sample at Dyngby.

Havnø, Eskelund and Lystrup The intention was to have 20 thin sections from each of the three sites. This was a fairly small number but as the context of the samples was unknown and there was relatively little information on the sites these were considered as part of an experiment to see if a reasonable interpretation of seasonality could be made from such small samples. 77

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Archaeological Interpretation Once the shells had been sub-sampled they were then thin sectioned, and as shown in the last chapter, shells from some sites survived the process better than others. Seasonality readings were taken from the archaeological oysters in order to understand more of scheduling and procurement patterns which can contribute to seasonality studies for the Ertebølle period. It was also important to ascertain the age of the oysters to see if certain sizes of oysters were being exploited, as well as comparing age with shell size to see whether anthropogenic or environmental influences were affecting growth through time and between sites. As discussed in chapter 3 problems arise when interpreting archaeological shellfish, in that the interpretation of season of death and age largely relies on making the assumption that growth in modern controls is analogous to growth in archaeological specimens. A comparison of environment and climatic conditions is made in this chapter although the data used is crude. It is therefore important to make the point that interpretation is not precise and trends in the data should be identified, rather than attempting to pinpoint a month of death for each shell. This chapter described the results of the thin sectioning, it makes a comparison of past climatic conditions with those of the present day, and interpretations of seasonality and age are presented for each site.

CHAPTER 8

Thin Sectioning Other than the shells from Lystrup the archaeological oysters were fairly simple to thin section. On hindsight the oysters from Lystrup, being so fragmentary, should perhaps have been impregnated with resin prior to sectioning. This was avoided because it means the samples then have to be ground and polished by hand which tends to produce an inferior finish. It is also better to use exactly the same techniques for the control samples and the archaeological samples for comparative reasons. Having looked at these thin sections under the microscope many of the shells appear to have eroded prior to sectioning; it was not damage typical of breakage due to sectioning, see figure 8.1. Very few of the samples had retained their outer edge or their hinge surface where the ligostracum joins the shell matrix. It was therefore practically impossible to analyse any of the Lystrup sample.

growing edge

Figure 8.1: L.5.R. example of an eroded shell from Lystrup. The structure is broken and no interpretation as to age or seasonality can be made.

Apart from this site, the other thin sections tended to be relatively clear and easy to read. There appeared to be very few disturbance lines and when there were they could be easily distinguished from the annual lines. There were hardly any conchiolin lines at all. Some of the shells from Dyngby and Eskelund were stained by iron oxides and this sometimes obscured parts of the structure which made interpretation difficult. Figures 8.2 to 8.8 show examples of thin sections made from shells from the archaeological sites. It should be noted that the ligostracum has eroded away through time.

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growing edge 3

1 2

Figure 8.2: D.1.16.R. Oyster sampled from section1, Dyngby. There is some iron oxide staining on the tip (on the right). A line can clearly be seen forming on the edge, and 2 other annual lines are visible

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growing edge

1 2

3

Figure 8.3: E.25.R. An oyster from Eskelund. Although the edge is a little broken at the top, it can be seen that there is a line 0.2mms in from the edge. There are 2 other annual lines

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growing edge

3 2

1

Figure 8.4: E.27.L. An oyster from Eskelund. There is a line about 0.3mm from the edge, and what appears to be 2 other lines in the structure. This shell is interpreted as being harvested in May/June.

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growing edge D

3 1 2

Figure 8.5: V.1.3.R. An oyster from sample 1, Visborg. Three annual lines can be seen. Darker disturbance can be seen in the last 2 bands. This shell has been interpreted as being gathered in August or September from the patterning of the structure. The darker areas have been affected by heat.

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growing edge

1

4 3

2

Figure 8.6: H.1.L. A very clear thin section from an oyster from Havnø. A line is forming on the edge. Three other annual; lines are visible and these have dips in the boundary. Line 4 , very close to the hinge tip, is not as clear as the other lines.

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growing edge

1

2

Figure 8.7: N.5.8.L. An oyster from the Neolithic levels of Norsminde. A line has just formed on the edge.

86

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growing edge

1

2

Figure 8.8: N.9.8.L. An oyster from the Mesolithic levels of Norsminde. Although some of the shell is broken a line can be seen to have formed on the edge.

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It was shown in chapter 3 that the three locations of Chelmsford, Truro and Southampton had varying climatic conditions. Those sites near Chelmsford tended to have hotter summers with averages of about 20°C, but often reaching about 25°C. In the winter months the sea temperatures tended to drop to less than 5°C, sometimes almost reaching freezing point. The salinities tended to fluctuate around 29‰. At Southampton and Truro on the other hand the summer temperature equalled or was below 20°C but in the winter it rarely dropped to below 5°C. At some of these sites salinity fluctuated greatly. Differences between sites and locations were also noted from colour, size and epifauna on the exterior of the shell but it was seen in chapter 5 that in fact the oysters tended to grow in the same manner. A line generally formed in March or April and growth slowed down again around October. Looking at the temperatures of the sea during these months it can be seen that these events appear to occur when the sea temperature is about 7°C.

Interpretation The Ambient Environment The great stumbling block in performing seasonality studies is the fact that one can never be sure how similar the environment, and hence the growth patterns of the species concerned, are to the present. The question must be posed as to whether the oysters which were gathered by the people of the Ertebølle culture in the Atlantic environmental period can be assumed to have grown in the same manner as those from the modern control sample. The problem with assessing this is that there is no detailed picture of the climatic conditions for each site and the time periods being considered span hundreds of years. It is thought that the temperatures would have been 1.5-2.5 °C (Midgely 1992, 6) or 2-3°C (Iversen 1941 cited in RowleyConwy 1985) warmer than today. At this time the coastal climate is generally described as moist and temperate with a mean summer temperature of 20°C and a mean winter temperature of 1°C, which is higher than the average temperatures of modern Denmark (Andersen 1991). It is thought that the shallow and more saline waters, warmer temperatures, and probably greater tidal range would have meant that the marine food chain was extremely rich (Andersen 1995). In March and April there would have been a burst of phytoplankton and then a decline in the following months as organisms fed on it (Rowley-Conwy 1983).

Figure 8.10 is a graph of mean monthly temperatures for Denmark for the years 1996 and 1997 (Danish Meteorological Institute). If 2°C is added to the average monthly figures then the months of March/April and October/November show an average temperature of around 7°C. It should not, however, be assumed that the present day temperature curve follows the temperature curve of the Mesolithic. The key to ageing and assessing season of death is having an anchor in the yearly cycle of growth. Although it is not known exactly when the Mesolithic oysters would have formed the annual lines, and even whether these lines do actually represent annual events several facts promoted confidence in the assumption that the lines were formed in a similar manner and time as the modern control sample. Firstly, when viewing the thin sections there is little difference between the lines and the structures of the archaeological and modern oysters except that the archaeological ones appear to be clearer. Secondly, the temperature and salinity readings for Chelmsford, Truro and Southampton were significantly different and yet growth in the oyster has been shown to be extremely similar. Thirdly, the time span of March/April, used as a anchor for annual line formation in the modern samples, is in fact quite broad.

Using the averages of 20°C for the summer and a mean winter temperature of 1°C (Andersen 1991) is too simplistic for this analysis. These figures do not indicate when temperatures may reach a point high enough for oyster growth to resume, neither do they consider variability between areas. Average British temperature from the Meteorological Office for the summer of 1997 was 15.4°C, and for the winter 4.11°C (Figures quoted from the Press Office 1998). These are averages based on temperature readings from 3 sites across England. Figure 8.9 however, shows temperature curves for 2 sites in England and how temperatures vary by a couple of degrees between years as well as between sites. It is likely that at the time of the Ertebølle culture there were similar micro-climates and there is of course evidence for this from the various size distributions of the oysters from the different sites.

It is acknowledged that using modern control samples as an analogy to the archaeological samples is not ideal but until more information is available as to the environmental conditions of the various sites it is impossible to attempt any other approach. The method of interpretation used on the modern control sample was therefore used on the archaeological shells. The way in which the results are viewed, however, will influence the final interpretation as shown in chapter 5. Because there are problems with comparing modern and archaeological samples from different environments the seasonality of each oyster will not be considered individually. Instead, the results will be assessed by looking for groupings or spreads to show evidence for differences in patterns of procurement, as well as for temporal and spatial differences.

A reconstruction of sea temperatures could theoretically be achieved through oxygen isotope analysis. This is not feasible on oysters, however, because of their sensitivity to salinity changes and it was attempted on periwinkles for the site of Norsminde but the fluctuating salinities in the fjords made it unfeasible (Deith 1985). Even if these temperatures were known, the past environments could not be fully reconstructed. Although controlled laboratory experiments could be carried out where temperature could be varied and responses by the oysters to the changes monitored there are too many other unknown variables such as the amount of food, salinity fluctuations, storms, predators, tidal amplitude and so on. 88

ARCHAEOLOGICAL INTERPRETATION

25 Camborne 1996 Camborne 1997 Southampton 1996

degrees centigrade

20

Southampton 1997

15

10

5

0 Jan

Feb

March

April

May

June

July

Aug

Sept

Oct

Nov

Dec

Figure 8.9: Average monthly temperatures for two sites in Britain, Southampton and Camborne for the years 1996 and 1997. Data provided by The Met. Office. 25

1996 1997

20

degrees centigrade

15

10

5

0 Jan

Feb

March

April

May

June

July

Aug

Sept

Oct

Nov

Dec

-5

Figure 8.10: Average temperatures for Denmark for the years 1996 and 1997. Information provided by the Danish Meteorological Institute.

89

CHAPTER 8 The random sample shows a high concentration in March and April but also an oyster collected in October.

Seasonality To assess seasonality each thin section was examined and a month of death was assigned using the same indicators as used for the modern control sample, described in chapter 5. These results and the notes made for each oyster are documented in Appendix 3. The seasonality for the individual sites was analysed by tallying each month for every sample point. If an oyster’s seasonality was estimated as two months, i.e. March/April, half a mark was tallied to each of the months. The data are presented in histogram form below. This form of representation has been used to emphasise the spread of the data through the year rather than using statistical tools such as means and standard deviations which obscures ranges and makes the data normative.

35 30 layer 7 layer 8 layer 9 layer 10

frequency

25 20 15 10 5

The 10 layers from Norsminde have been split into the Mesolithic (layers 7-10) and Neolithic (layers 1-6). Figure 8.11 shows the distribution of results from the analysis of the shells from the Mesolithic layers. The majority of shells in this case appear to be clustered around the months of March, April and May, with very few samples from the summer months; 1 in August and 1½ in June. Bearing in mind that every interpretation may incorrect by a month either way the concentration could be slightly greater about April, or may in fact be a little more spread out. Even so the interpretations are fairly tightly concentrated about the spring months. There does not appear to be a great difference between the 4 layers. Those oysters from layer 10 may have been collected in the later spring months, and those from layer 8 in the early spring months, but the modal class for all four layers lies in April.

ov

D ec

N

O ct

Se pt

Au g

Ju ly

Ju ne

M ay

Ap ril

Fe b M ar ch

Ja n

0

Figure 8.11: A histogram showing the frequency of estimated months of death for 50 oysters which came from the Mesolithic layers of the column sample from the Norsminde midden. 35 30

Layer1 Layer2

frequency

25

Layer 3 20

layer 4

15

layer 5 layer 6

10 5

The overall sample size of 46 shells from the Neolithic levels of Norsminde is comparable with the sample size for the Mesolithic layers. The frequencies for the individual months however, are much lower because the data is spread over more of the months, especially into the summer months of June, July and August, figure 8.12. The modal class for this histogram is May (N=13.5) but April has also got a high frequency of counts (N=11). Some of the gathering periods for individual layers differ slightly. In layers 2 and 3 most of the oysters appear to have been collected from May to August. Going down towards the lower layers 5 and 6, the majority of oysters tend to have been collected in the earlier, spring months.

ec D

No v

O ct

Se pt

g Au

Ju ly

Ju ne

ay M

Ap ril

M

ar ch

b Fe

Ja n

0

Figure 8.12: A histogram showing the frequency of estimated months of death for 46 oysters which came from the Neolithic layers of the column sample from the Norsminde midden. Dyngby, also shows a convincing scattering of collection events across most of the year, figure 8.14. The collection of oysters clearly spreads into the summer months and through to September. The modal month is March (N=7), and there is a concentration of gathering events around the spring months although it is not so pronounced as for Visborg and Mesolithic Norsminde. Sample 1 shows a clustering around late winter, early spring. Samples 2 and 3 however, collected from a different section, show a grouping around late spring, and summer, with the exception of some oysters in sample 2 which appear to have been gathered in March. The random sample shows a distribution from March to September.

The spread of months of collection for Visborg is also wide, from January right through to October, see figure 8.13. The modal class is March (N=15), and the spring months of March, April and May seem to be the months when most exploitation has taken place. It is unlikely that the spread is error in interpretation because the months other than March and April account for a third of the whole sample. The oysters from sample 1 appear to have been gathered from March through to September. Sample 2 which was taken from directly above shows a similar spread from January through to September. The oysters sampled from points 3 and 4, taken from a different section in the excavation area, show more of a concentration of gathering in the late winter and spring months. Again sample 4 was taken directly above sample 3.

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ARCHAEOLOGICAL INTERPRETATION 16 10

14

random sample sample 4 sample 3 sample 2 sample 1

10

9 8 random sample

7

8

frequency

frequency

12

6 4

6 5 4 3

2

2

De c

De c

No v

O ct

Se pt

Au g

Ju ly

Ju ne

M ay

Ap ril

Figure 8.13: A histogram showing the frequency of estimated months of death for 38 oysters which came from 4 sampling points and a random sample at Visborg.

Fe b M ar ch

0

Ja n

No v

ct O

Se pt

Au g

Ju ly

Ju ne

M ay

Ap ril

M ar ch

1

Fe b

Ja n

0

Figure 8.15: A histogram showing the frequency of estimated months of death for 15 oysters which came from a random sample from the midden at Eskelund.

10 10

9

8

5 4 3

6 5 4

de c

no v

oc t

se pt

au g

ju ly

ju ne

ja n

m ay

0

D ec

N ov

ct O

Se pt

Ju ly A ug us t

Ju ne

1

M ay

0

Ap r il

2

M ar ch

3

1

Fe b

2

Ja n

random sample

7

ap ril

6

frequency

frequency

9

random sample 3 sample 2 sample 1

7

fe b m ar ch

8

Figure 8.16: A histogram showing the frequency of estimated months of death for 13 oysters which came from a random sample from the midden at Havnø.

Figure 8.14: A histogram showing the frequency of estimated months of death for 21 oysters which came from 3 sampling locations and a random sample from the midden at Dyngby.

10

The samples from the three sites of Eskelund, Havnø and Lystrup were random samples of oysters. There is no way of knowing where in the middens these samples came from but they should give an indication of some of the months in which the oysters were gathered. A total of 15 shells was interpreted from the Eskelund sample. These oysters show a spread of collection events from March through the spring and summer months to August, figure 8.15. The modal month is March (N=8). The modal month for the site of Havnø is also March (N=9.5) but in this case the sample is not spread over many months, only covering early spring, figure 8.16. The sample size is however very small (N=13) and therefore is unlikely to be representative. The shells from Lystrup were very damaged and therefore the total number of shells which could be analysed was only 4. This is too small to make any interpretation from, but the results of those which were assessed have been plotted on figure 8.17. This shows that one oyster was collected each month from April to July.

9 8

random sample

frequency

7 6 5 4 3 2 1

De c

No v

O ct

Se pt

Au g

Ju ly

Ju ne

M ay

Ap ril

M ar ch

Fe b

Ja n

0

Figure 8.17: A histogram showing the frequency of estimated months of death for 4 oysters which came from a random sample from the midden at Lystrup.

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18 16 14

hinge length (mms)

12 10 8 6 Eskelund Havno Mesolithic Norsminde Dyngby Visborg

4 2 0 0

1

2

3

4

5

6

7

8

9

10

age

Figure 8.18: A graph to show estimated ages plotted against the approximate length of the hinge (in mm) for the sites of Visborg, Dyngby, Eskelund, Havnø and the Mesolithic layers of Norsminde. Lystrup has not been included because these age and measurements could only be ascertained for 3 of the shells. 18 16 14

hinge length (mm)

12 10 8 6 4 Mesolithic layers Neolithic layers

2 0 0

1

2

3

4

5

6

7

age

Figure 8.19: A graph to show the difference between the oysters age and hinge lengths in the Mesolithic and Neolithic periods at Norsminde.

92

ARCHAEOLOGICAL INTERPRETATION Comparing the difference between shells taken from the different sampling points at Visborg is more problematic because the sample sizes are fairly small. Figure 8.20 shows that oysters from sample 1 at the bottom of the section may on average be slightly older than those at the top. Those taken from the other section also show that the oysters at the bottom (sample 3) are slightly older than those from the top. It is difficult however, to assess whether those from the bottom of the sections are also larger for their age because the sample sizes are too small.

Age In the blind testing of chapter 6 it was concluded that ageing of oysters was difficult but it was also acknowledged that in modern control samples disturbance lines can often be mistaken for annual lines. These are caused by events such as spawning, predator attacks or storms. In the archaeological samples the structure is often much clearer and disturbance lines are fewer and therefore it is likely that the reliability of the age readings is greater. It should be reiterated here that a count of annual lines do not represent the age of the oyster as such, but simply how many springs the oyster has lived through. Two oysters collected in March may be technically the same age, i.e. they were ejected into the sea as larvae at the same time but they may not form their annual lines at exactly the same moment. One may have started growing slightly earlier and may have formed a line. Here age would be 4 for example, but the other may not have formed a line and age will be counted as 3. Therefore the ages must only be taken as approximate, and again this is another reason why large sample sizes are needed.

It was seen during excavation at Dyngby that the oysters near the top of the exposed section were a lot smaller than those nearer the bottom. The age analysis in figure 8.21 shows that this is due to age, those at the top being younger. Those from sample 1 are also relatively young. The sample sizes here are again too small to adequately compare age and size to see whether the oysters are actually becoming smaller for their age as well as younger at the top of the midden. In conclusion the size and age distributions vary from site to site. There is a slight decrease in size of the oysters in the Neolithic layers of Norsminde compared to the oysters from the Mesolithic layers but this is probably attributable to a change in environmental conditions from the Atlantic into the Sub-Boreal phase. The average age of the oysters collected in the Neolithic also appears to have decreased. The oysters at the top of the Dyngby midden are visibly smaller in section because they are younger. This is the same for Visborg.

The ages were interpreted for each archaeological oyster and these results are included in Appendix 3. To see how the age of the oyster relates to size at the different sites the estimated ages have been plotted against hinge length, figure 8.18. The hinge length was used rather than shell length because complete valves are not often found in middens, and the hinge survives better. The hinge length was measured at the categorisation stage prior to sectioning. These measurements were made in millimetres using electronic callipers from the tip of the hinge to its growing edge, as with the modern control sample. As the shell does not always grow symmetrically but sometimes skews to the side the measurements can also only be taken as approximate.

Summary The archaeological oysters were thin sectioned and analysed in order to obtain age and seasonality data. The sampling procedure was seen as experimental, and has shown that sampling from different sites and different areas within a midden can produce interesting results. If for instance the site of Norsminde had solely been used, as originally intended, it may have been concluded that oysters were being gathered exclusively in the spring and it would not have been seen that oysters were being collected through the summer at other sites. The intra-site sampling strategies produced similar data. If at Visborg only one area had been sampled the spread of months would not have been picked up; if points 1 and 2 had not been sampled then it may have looked like the oysters were only being gathered in late winter and spring. The same is true of Dyngby; if the exposed section of points 2 and 3 had not been sampled then once again it would have looked as if most of the oysters were being collected in late winter and spring.

It has already been noted that the shells from Dyngby were very small but there was always the possibility that this was due to environmental influences. In fact this graph shows that these shells are very young in age. They do, however, appear to be on average slightly smaller than the oysters of the same age from other sites. Eskelund also follows this pattern. Visborg and Havnø on the other hand appear to have oysters which are much older and slightly larger for their age. The oysters from the Mesolithic layers of Norsminde fall more in the middle, having a wide spread of ages and hinge lengths. There is obviously a difference in oyster sizes and hinge lengths from site to site but this may simply be a product of micro-environments around the coast. It was shown from the modern control samples that shells from the Chelmsford locations grew much larger than those on the south coast of England due to more favourable conditions (temperature, food, salinity etc.).

Although the results are convincing, the study would have benefited from even larger sample sizes. This would have allowed a better comparison of oyster size and age for the sites of Dyngby and Visborg. The sample sizes for the sites of Lystrup, Havnø and Eskelund were far too small for any reliable interpretations of seasonal patterns in exploitation of the oyster to be made.

On an intra-site scale, when the oysters from the Mesolithic and Neolithic layers of Norsminde are compared, see figure 8.19, it can be seen that those oysters from the Mesolithic layers are on average slightly larger for their age. There are also more oysters 4 years and over in the Mesolithic layers.

93

CHAPTER 8

18 16 14

hinge length (mm)

12 10 8 6 sample sample sample sample

4 2

1 2 3 4

0 1

2

3

4

5

6

7

age

Figure 8.20: A graph to show the difference between the oyster age and hinge length for the 4 sample points at Visborg. Sample 1 was taken from the bottom and sample 2 from the top of an exposed section in one area of the excavation. Sample 3 was taken from the bottom and sample 4 from the top of an exposed section in another area of the excavation. 18 16 14

hinge length (mm)

12 10 8 6 sample 1 sample 2 sample 3

4 2 0 1

2

3

4

5

age

Figure 8.21: A graph to show the difference between oyster age and hinge length for the 3 sample points at Dyngby. Sample 1 was taken from an exposed section in one area of the midden. Samples 2 and 3 were taken from another exposed section further to the west. Sample 2 was taken from the bottom of the section and sample 3 was taken from the top.

94

CHAPTER 9

Discussion The aim of this research was to develop a method for analysing the seasonality of the European oyster, Ostrea edulis. This volume has presented a methodology which has been verified with blind testing and applied to samples of oysters from six prehistoric Danish shell middens. The work has presented a new line of evidence that can contribute to an understanding of seasonal food consumption in Danish prehistory. It has, however, also turned up a host of new questions. What the results appear to show is that the exploitation of oysters is not simply limited to one particular time of the year. There is some intra- and inter- site variation and this can only be elucidated further by more sampling. These results have therefore brought up a set of issues concerning sampling strategies. In addition, ageing of the oyster shells has also allowed a comparison of size and age which may shed some light on the changing shell sizes through the middens. This chapter will bring together these results and resulting questions in the context of the Ertebølle period and the transition to agriculture, and avenues for future research will be suggested.

CHAPTER 9

Methodology

The method of thin sectioning is not often attempted in such studies, probably due to higher costs and time input compared to other methods, such as taking acetate peels. Thin sectioning proved worthwhile, however, in that the changes in structural growth and colour could be seen clearly, facilitating the identification of annual lines. This method could also be used on the hinge area of the shell. The incremental growth structures are visible in the hinge and this is one of the more robust areas of shell which survives well in the middens.

investigated then it is important to have large enough samples from each location or level. The sample sizes from Dyngby and Visborg are fairly large as a total but the sample sizes from individual contexts are in fact very small, all under a total of 11 shells. The seasonality results from these contexts have been compared in the last chapter but the interpretations might have been reinforced if the sample sizes had been larger. Similarly, the sample sizes for the individual contexts of Norsminde are small but these have been grouped into Mesolithic and Neolithic categories which have increased the sample sizes significantly making it possible to compare seasonal oyster consumption through time. However, at this site there is no analysis of spatial variation and it has to be assumed that the results are representative for the midden as a whole.

The modern control proved to be a vital part of the methodology. It was clear that large sample sizes were needed and oysters were gathered from different regions along the British coast to assess variability of growth. Despite differing ambient environments and differences in shape and size between locations, evidence for annual line formation and structural patterning was shown to be broadly similar between locations. This could be tested further in the future by sampling oysters from more northern and southern locations along their geographical range. It would also be useful to understand more about how the different variables such as temperature, food and salinity affect growth and at what point changes in these variables significantly alter events such as annual line formation. In this study, after comparing the available data on past and present environments the assumption was made that growth of the modern and archaeological oysters was probably fairly similar.

If the sites have already been excavated there is less control over where the shells may be sampled from, and the reality may be that the shells represent a random sample from the whole site, as with the samples from Eskelund, Havnø and Lystrup. Again, are the sample sizes from these sites really large enough to make any meaningful assessment? The samples from Eskelund and Havnø total 15 and 13 respectively but there were only 4 shells from Lystrup. It is felt that particularly at this latter site the results can tell us little, except that these 4 shells had been gathered sometime in the spring and summer. We do not know whether this is representative or not. It is interesting to note here that if these sample sizes are compared with many other seasonality studies, both for shellfish and other animals (see for example the analysis in chapter 1, and Claassen 1998, 154 and table 9, 156) these sample sizes are not out of place, and in some cases are comparatively large!

The interpretation of season of death was made by “eyeballing”, as opposed to measuring. This is perhaps not an objective approach, however, blind testing on the modern controls was conducted to prove a level of accuracy. The blind testing demonstrated that 91% of interpretations were correct within the error of +/- 1 month. A “novice” test was also performed, showing that a great deal of experience is needed before interpreting the thin sections.

Part of the problem with sample sizes was that a loss of shells through the processes of thin sectioning and interpretation was not anticipated at the sampling stage. An examination of the sampling strategy shows that usually 20-25% of the sample is discarded during these processes, unless the shells are in a really bad condition, when more shells are lost. When sampling, therefore, the fact that a fifth to a quarter of the sample may not be usable should be taken into account and a larger number of shells should be sampled.

The main aim of the research was to develop a method for analysing the incremental growth in the shell of the European oyster, Ostrea edulis, in order to ascertain season of death. This has never before been attempted for this species but was achieved by tailoring the techniques of thin sectioning.

In terms of interpretation it is necessary to reiterate the point that we should not strive to be over-precise. The month assigned to each shell is +/- 1 month. Therefore rather than considering the seasonality of each shell it is important to look for patterns and grouping within the data for each context. Perhaps in future work it may help to divide the year into 5 or 6 “seasons” which are related to structural change in the shell, as suggested in chapter 6.

Even with small sample sizes, however, some of the results do appear to be valid. For instance there is a clear difference between Neolithic and Mesolithic seasonality at Norsminde. However, for more refined interpretations, when looking at intra- and inter- site variability, it is clear that larger samples are required. It should be noted that sample sizes are often small because of the preliminary nature of the analytical techniques, uncertainties about their validity or accuracy, and the time and expense involved in their application. The results in this study have demonstrated that the techniques produce coherent and interpretable results within measurable limits of error, and therefore the greater time and expense of working on larger samples in future work is fully justified and would be worthwhile.

Sampling What is a valid sample size? This depends on the question being asked of the sample. If intra-site variation is being

96

DISCUSSION

Seasonality results

resources may have been available but were not necessarily abundant or productive enough.

To summarise the results, Mesolithic Norsminde and Havnø demonstrate very seasonal gathering, concentrated within a narrow season during the spring. Visborg, Dyngby, Eskelund and Havnø all show a peak of gathering in spring- March, April and May. Despite this pattern of spring gathering, for many of the sites there does appear to be evidence for gathering oysters later on in the year as well. The oysters from the Neolithic layers in Norsminde reveal spring and summer gathering, as do those from Eskelund. The oysters from Visborg reveal gathering from January through to October, and those from Dyngby gathering from January through to September. Taking into account the fact that it is very difficult to assign a month of death to those oysters which die between November and February, it may be that some of the “winter” shells from these sites may have been assigned the wrong months. It is not impossible therefore, that there was continuous gathering throughout the year, a possibility which can only be confirmed through further analysis.

Secondly, Jochim (1991) has argued that the concept of a “seasonal round” is normative and takes little account of both differences among individuals or families, and changes from year to year. In fact, he argues that archaeologists should not attempt to follow ethnographers in reconstructing the seasonal round because it may not even exist (Jochim 1991, 315). Many archaeological sites are palimpsests of information. If poor stratigraphic resolution makes it impossible to isolate the individual episodes of use, the aggregated data may give the illusion that the site was used throughout the year. In reality the site may never have been used for more than a restricted season in any given year (Rocek 1998). Although the positive aspect about shell middens is that they are often large, with thick sections and the potential for good spatial analysis it is still very difficult to achieve an understanding of accumulation rates. A mound of shell midden can represent refuse from small sporadic meals over a long period of time, or at the other extreme it may represent the aggregation of shells from a large, brief event, such as a feast. Given the often homogeneous nature of shell midden stratigraphy, it can be very difficult to define individual units of deposition.

Getting into even finer detail, at the site of Visborg there appears to be spatial variation between two areas of midden accumulation. In one area gathering may possibly have taken place throughout the year whereas in the adjacent area the results appear to show oyster gathering which was concentrated in the late winter and spring months. At Dyngby in one section there is evidence of late winter/early spring gathering and in the other section spring and summer gathering. At Norsminde too there is clear evidence for a change in practice, through time, with spring gathering in the Mesolithic and spring and summer gathering in the Neolithic.

In a similar vein, although it may be inviting to attempt to connect Norsminde with other sites in the landscape this should only be done with caution. At Norsminde there is evidence for seasonal activity for most of the year (see chapter 7) however it could be argued that there is little winter activity. The site of Ringkloster, inland about 14 km to the west of Norsminde, is an extensive site with evidence for occupation through the Ertebølle and into the Early Neolithic (Andersen 1998). The seasonality data from wild boar, red deer and roe deer as well as pine martin suggests that this was a site used in the winter and spring (Rowley-Conwy 1998). As several lines of evidence suggest contact with the coast, including 13 oysters, saltwater fish bones and the ribs of a bottle nosed dolphin, it is tempting to link this with sites such as Norsminde. However, both analyses of seasonality are using palimpsests of data and both sites span hundreds of years of occupation. These sites could be linked in order to try and create a picture of the seasonal round, however there is the possibility that they were never used contemporaneously by the same people.

Perhaps these results are not entirely surprising. Should we really be expecting that people in the late Mesolithic and early Neolithic in Denmark all collected oysters at precisely the same season every year? All sorts of factors may have come into play which influenced their decisions about consuming oysters (Milner 2002). These may have been decisions based on economic, environmental, social and/or ritual elements of their lifestyle and may have changed from time to time, again for all sorts of reasons. It may be, for instance, that at Norsminde the spring time was a very lean period and oysters played a role in “plugging the gap”, as suggested by RowleyConwy (1984). Alternatively, or perhaps even inter-linked, the seasonal exploitation of oysters in the spring may have been connected with some spring ritual. We can hypothesise about why people were collecting oysters at certain times of the year, but these ideas are difficult to prove.

The situation may in fact be far more complex with different groups of people occupying different ecological niches within one area (Jochim 1981). The Anbarra are just one of a number of Gidjingali speaking people who hunt, gather and fish in Arnhem Land, Northern Territory, Australia (Meehan 1982). Over the study of a year’s seasonal cycle it was shown that they moved four times between beaches and inland for a ceremony. Two of the other groups, the Matai and Gulala, lived in quite different ways, occupying at least a dozen sites, some of which were probably occupied twice. One of the Anbarra referred to the Gulala as “rough sea people” spending most of the year going up and down the coast and sailing their canoes. The Matai on the other hand were thought of as “forest people” afraid of the sea and inclined to stay in the forest environment.

Seasonality is often used in discussions of Mesolithic settlement, sedentism and mobility. However, at the moment, without a finer resolution of seasonality data for other species as well, we still appear to be where we were in chapter 1, i.e. we can argue either way for sedentism or mobility at these sites. There are several problems associated with trying to use seasonality data to get an understanding of these issues. Firstly, year round availability of resources is often used to suggest sedentism. However, as Spikins (1999) notes, the 97

CHAPTER 9 Up until now sampling and seasonality studies have not taken much account of these issues. However, it is now feasible to study the seasonality of the oyster, a major component of many of these middens, and this can be used in conjunction with other well-established techniques for other faunal remains. It may also be possible in some cases to further understand midden accumulation rates through stratigraphical approaches to midden excavation (Stein 1991). In addition, amino acid racemisation (AAR) analysis has the potential to offer a rapid and relatively cheap method of providing information on the extent of stratigraphic mixing within a midden, provided a closed system (such as intra-crystalline amino acids) is analysed (Collins and Riley 2000). With these methods and approaches and a careful sampling strategy that takes into account the nature of palimpsests it should be feasible to measure variability through time and space. Only then can we begin to construct more complex models of behaviour and address some of the above issues.

Many isotopic studies on human bones are now showing a dramatic shift in food consumption across north-west Europe at this transition phase, with marine foods playing a dominant role in the diet in the Mesolithic and terrestrial foods playing a dominant role in the diet in the Neolithic (e.g. Tauber 1981; Richards and Hedges 1999a, 1999b; Schulting and Richards 2000). Yet there still appear to be shell midden sites in the archaeological record which demonstrate that marine foods were still being consumed in the Neolithic. We need to know more about the frequency, the nature and the seasonality of this practice. Was it, for instance, a regular occurrence at the lean period of the farming calendar, the summertime prior to the harvest, or was it an emergency response in the leaner years? At Norsminde there is only evidence for shellfish gathering. No fish bones were found in the Neolithic part of the midden at all, although fish may have been taken away to other sites or processed differently. At the shell midden of Bjørnsholm there is still evidence for fishing in the Neolithic in addition to shell gathering. How do these sites fit into our concepts of early Neolithic communities? Shell midden sites are an excellent resource that can be used to answer some of these questions but again we need more detailed information on seasonality and on accumulation rates.

Changing practices are also especially interesting for the study of the transition to agriculture. At Norsminde there is a clear shift in the seasonal gathering of oysters from the Mesolithic to the Neolithic. This is combined with a dramatic change in midden composition from a predominance of oysters in the Mesolithic layers to mainly cockles in the Neolithic layers. In addition the shellfish become smaller in size and there are large amounts of charcoal and burnt stones in the Neolithic layers. What are the reasons for all these changes? Environmental change has been one of the arguments used for the transition to agriculture in this area (see chapter 1). Part of the hypothesis suggests that a lowering of salinity resulted in an oyster decline causing oysters to no longer fill the role of “plugging the gap” in the seasonal round (Rowley-Conwy 1984). The size/age analysis of oysters in this study has shown that rather than yearly growth bands becoming smaller the oysters are in fact becoming younger. What this means is that the decrease in size is due more to a reduction in average age rather than a decrease in growth rates. This type of pattern is often interpreted as being indicative of human overexploitation. Claassen (1998, 47) states that many such interpretations have never been proven, however the age of shellfish are rarely taken into account in these studies. This is a complex issue and requires further analysis of both the shellfish and other environmental indicators. It may be that a combination of factors accounts for a decrease in size. It does not necessarily follow, however, that a decline in oyster size is the reason for a decline in gathering in favour of cockles, and neither does it mean that this decline was the catalyst for the adoption of agriculture.

Conclusion This study has shown that: • It is possible to obtain seasonality information from the oyster, Ostrea edulis, through the study of modern controls and the technique of thin sectioning • A study of 6 archaeological sites from Denmark has shown that there may be variability of oyster gathering through time and space • It is possible to obtain data on the age of the oyster, which can be used to investigate size changes through time There are many methods available that may be used to elucidate seasonality but in order to approach an understanding of past activities we need good quality data. This can only come from using large samples, where possible, and from testing across space and time. Rather than attempting to force the seasonal data to fit a hypothetical seasonal round we should, perhaps, be embracing variability. In this way we may be able to understand more about practices both in the Mesolithic and the Early Neolithic, as well as during later periods that have shell middens. Incremental information may also be used to investigate the environmental context, monitoring changes through time and providing insights into the impact humans may have had on the ecological niche they were exploiting.

It is possible that the great change that occurs in shell middens at this time, may in fact be a result of the shift in lifestyles and practices, rather than a reflection of an environmental change. With the advent of the Neolithic, settlement patterns and subsistence changed and the people who were still consuming marine resources at Norsminde gathered oysters in the summer as well as the spring. More work on more oysters from the individual layers together with seasonality work on other species, such as cockles, would enable us to understand more about these changes.

In this volume I have not attempted to explain the transition to agriculture, or Mesolithic lifeways. There are still many unresolved issues and this study has thrown open many questions. I hope however, to have demonstrated a technique which may be applied to many sites in Europe, and to have shown that the application has important potential to raise new questions and suggest alternative approaches in the study of prehistory. 98

APPENDIX 1

Appendix 1 This appendix includes notes and measurements made for the thin sections of the modern control sample. The codes for the samples may be found in chapter 4. The age column gives the number of annual lines identified. The notes are transcribed from records made when analysing the thin sections under the polarising light microscope in February 1998, after all the thin sections of both modern and archaeological samples had been made. Certain observations were made, e.g. how clear the annual lines were, if there were any disturbance lines such as mid-lines or conchiolin lines, and structural and colour changes. The annual lines identified were numbered back through the sample, so the newest line nearest the edge was 1, the next 2 and so on. The year 0-1 represents the measurement between the last line and the growing edge, the year 1-2 would represent the previous years growth etc. If a line has just formed or is forming on the edge the year 0-1 would be the measurement of the last band, that is between the line on the edge and the previous line. Measurements are in millimetres. The records marked in bold indicate that the photograph is included in chapter 5 and therefore the notes can be cross-referenced with these. It can be seen that some of the slides are re-makes or doubles, i.e. both the left and right half of the sectioned valve were sampled, e.g. C.2.J.11.L and C.2.J.11.R and a re-make was made of the right block, C.2.J.11.Ra. See chapters 3 and 4 for more details.

Chelmsford Identity

Site A C.1.A.6.R C.1.A.7.R C.1.A.8.L C.1.A.10.L C.3.A.9.L C.3.A.11.L C.3.A.12.R C.3.A.13.L C.3.A.15.R C.4.A.11.R C.4.A.15.R C.5.A.13.R C.5.A.20.R C.6.A.14.L C.6.A.17.L

Date

Age

Notes

02-Apr-96 5? clear lines, one line forming on edge 02-Apr-96 4?5? cut on angle? line at edge, mid-lines resemble annuals, structure helpful 02-Apr-96 4 bit broken, edge intact, line forming at edge, clear but thin slide 02-Apr-96 3 3 very clear lines, dipping on edge and triangle, line about to form 13-May-96 4 4 lines, one just formed on edge, last year difficult, mid-line with big dip 13-May-96 4 very clear structure, line 0.2 mm from edge 13-May-96 4 very clear, line on edge, no mid-lines, maybe cut on angle 13-May-96 4 measurements odd, probably the cut, line on edge 13-May-96 4 measurements odd, probably the cut, line on edge, clear lines and no mid-lines 20-Jun-96 3 very clear, line 0.4mms from edge, annuals different from mid-lines 20-Jun-96 4 4 very clear lines, line at 0.25mms from edge 17-Jul-96 split down conchiolin line but can still identify line 0.5mms from edge 17-Jul-96 3?4? slide thick, no mid-line complications, structure clear, line 0.3mms edge 30-Aug-96 3?4? last line 1.1mms from edge, no dipping yet 30-Aug-96 3 last line 1.4 mm from edge, no dipping yet, should

99

Years 0-1

1-2

2-3

3-4

1.6 2

1.6 1.9

2.2 1.5

2.4 4.0? 3.2

1.9

1.2

2

1.8

2

1.8

2.3

1.9

1.5

0.2 0.01

1.8 1.9

2.1 2.4

2.9 3.2

0.1 0.1

0.7 1.8

1.8 2.7

3 4.2

0.4

2.5

2.9

0.25 0.5

1.5

2.4

0.3

1.5

2.2

1.1 1.4

1.9 2.6

2.5 2.2

2.8

3.1

4-5

APPENDIX 1

C.7.A.14.R C.7.A.15.L C.8.A.13.R C.8.A.17.R C.9.A.9.L C.9.A.14.L C.10.A.15.L C.10.A.16.R C.11.A.13.L C.11.A.14.L C.12.A.11.L C.12.A.12.L C.12.A.14.L C.12.A.15.R C.12.A.16.L C.13.A.7.R C.13.A.10.L C.13.A.12.L C.13.A.14.L C.13.A.16.L C.13.A.18.L

Site D C.1.D.10.L C.1.D.15.L C.2.D.11.R C.2.D.14.L C.3.D.14.L C.3.D.20.L C.12.D.14.R C.13.D.15.R

get about August very thin slide, fairly clear, line 1.5mms from edge, 1.5 no dipping 17-Sep-96 3 very strange, measurements all wrong, line only 0.25 0.25mms from edge 18-Oct-96 4 lines and structure clear, slightly damaged at 1.5 growing edge, not severely, ligostracum missing 18-Oct-96 4 lines clear, no obvious mid-lines, beginning to 1.2 dip, structural patterning 21-Nov-96 3 very thin slide, lines clear, no dipping, false line near 0.8 edge but not much of a dip yet 21-Nov-96 3 lines clear, edge dipping over a little, triangle 1.6 has formed 13-Dec-96 2? would probably get this one wrong, measurements 1.2 deceiving, no dipping, little triangle possibly 13-Dec-96 4 cut on a slant therefore measurements no help, sort 0.8 of mid-line last year, triangle forming, dips 22-Jan-97 3 patterning and growing edge should indicate 0.8 January, but no triangle, bit difficult 22-Jan-97 3? v. small triangle, dipping and measurement should 1.9 give some indication, lines and structure clear 07-Feb-97 2 difficult as very thin slide and ligostracum ground 2.4 out, some dipping and measurement clear 07-Feb-97 3 this may be assessed as earlier, no dip or triangle 1 and measurements no help, lines clear though 07-Feb-97 3 slide too thick, triangle and dipping, same amount of 1.1 growth as previous year 07-Feb-97 2? could easily get wrong, line near edge but 1.5 disturbance lines in last band, winter disturbance 07-Feb-97 3 dipping and triangle, lines very clear, measurements 1.7 not much help 05-Mar-97 3 Useless as most recent band been removed by ? grinding, probably 3 lines 05-Mar-97 3 looks like line is about to form on edge, dipping but 1.1 no triangle, lines clear but not spaced out 05-Mar-97 3?4? not much growth but a lot of dipping on edge, very 0.7 faint triangle, may possibly assess as earlier 05-Mar-97 3? false line near edge, some dipping at edge, no 1.8 triangle, last couple of lines very clear 05-Mar-97 3 does not dip much, no triangle but lines very clear, 1.5 as are measurements 05-Mar-97 3 triangle and dip, pattern indicates line about to form, 1.2 lines all very clear with dips 17-Sep-96

4

18-Mar-96 3?4? very clear, line forming at edge, dip and triangle and 1.4 ligostracum line, 18-Mar-96 2?3? fairly clear structure, one line about to form on edge, 2.2 dipping, not so sure about lines 2 and 3 15-Apr-96 4?5? line just formed on edge, triangle and dipping, clear 2 structure, lines clear breaks, mid-lines 15-Apr-96 broken ? 15-May-96 3 line forming on edge, little triangle, fairly clear 1.1 although possibly a little too thick 15-May-96 4 difficult slide, line right at edge, very big dip more 0.15 typical of disturbance line 05-Feb-97 2 fairly clear, may be another line, measurements a bit 1.4 odd, looks like line about to form, red line 07-Mar-97 4 one line right on edge, dip, other lines clear breaks, 1.2 100

2.6

3.2

3.4

1.5

3

2.3

2.4

4

1.6

2.1

2.1

1.4

2.3

2

2.9

3.7 1.6

2.1

1.5

2.9

2.5

2.4

3

3 1.7

2.5

1.1

2

2.8 2.3

3.5

1.5

2

1.2

1.8

1.7

2

2.6

2.8

1.6

3.5

1.7

2.6

2.2

1.5

2.9

1.4

1.4

1.5

2.2 1.8

1.4

2.6 2.3

3.2

1.3

APPENDIX 1

C.13.D.10.L

07-Mar-97

3?

C.13.D.14.R

07-Mar-97

3?

Site E C.1.E.18.L

18-Mar-96

?

C.2.E.17.R C.3.E.18.R C.4.E.13.L C.5.E.12.R C.5.E.16.R C.8.E.17.L C.9.E.17.L C.10.E.13.L C.11.E.11.R C.12.E.11.L C.13.E.9.L

hardly any disturbance very difficult, looks like line is about to form, triangle and dip, other lines not v. clear, disturbance last line very clear and red line against it, other two not so clear, edge a bit split

2.3

2.2

3.3

1.8

1.5

2.1

3

3.4

1.5

2.1

3.2

1.4

1.6

2

1.6

2.2

2.2

2.2

3

3

2.2

2.4

2.3

1

0.8

1.8

1.5

1.7

difficult one, there is a dip and little triangle but ? sample broken, probably along last line 15-Apr-96 3 edge dipping down, looks like a line is about to form, 2.2 others clear although disturbance lines 15-May-96 4 very clear structure, line clearly formed on edge, 0.05 may have been cut on angle 12-Jun-96 ? probably discard this one, lot of confusion around ? edge, many lines and darker patch 15-Jul-96 ? probably discard, likely to be an old shell, many ? lines and thick hinge, disturbance at edge 15-Jul-96 5? difficult one, one line right at edge, from structure 0.1 under low magnification look like 5 lines 09-Oct-96 3 fairly clear structure, dips with lines but also mid0.7 lines 11-Nov-96 3? difficult, looks like a line 0.4mms from edge but from 1.4 patterning probably a mid-line, v. similar 09-Dec-96 2?3? fairly clear lines with dips, red line occurring 2.1 immediately after last line, no dip but is triangle 22-Jan-97 4?5? very good example, very clear lines with dips and 1.3 lines in ligostracum, little triangle 05-Feb-97 4? measurements deceiving but may be the cut, red 0.7 lines occurring after the last 2 lines 07-Mar-97 3 very clear, lines all clean breaks, line forming on 0.8 edge, edge dipping right over

Site H C.1.H.13.R

19-Mar-96

2

C.1.H.14.L

19-Mar-96

2

C.2.H.12.L

15-Apr-96

1+

C.2.H.20.L

15-Apr-96

C.3.H.14.L

13-May-96

3?

C.3.H.18.L

13-May-96

3?

C.4.H.12.L

17-Jun-96

4

C.4.H.16.R

17-Jun-96

4

C.5.H.17.L

15-Jul-96

1+

C.5.H.19.L

15-Jul-96

3

C.7.H.11.L

11-Sep-96

2?

C.7.H.12.R

11-Sep-96

4?

C.8.H.9.R

14-Oct-96

4

dip on edge, looks like line is about to form, slide 2.8 rather thin but can still see structural changes slide very thin, lines not clear, more so under high 3.4 mag., dip and little triangle, line about to form top of the hinge missing, growing edge still visible, 0.1 line just formed with dip Useless, large part of growing edge region ground ? out some disturbance, not particularly clear, no doubt 0.5 about most recent line, rest not sure about badly made slide, very thin and cut badly, line right 2.3 on edge, third is not so clear most recent line very close to edge considering 0.05 June shell, clear line and dip though, mid-lines line very close to edge but all lines clear, occasional 0.1 faint mid-line most of shell been ground out, line near edge, had 0.5 problems with glue and bonding lines very clear, some mid-lines but much fainter, 0.2 lines in ligostracum and associated dips lines fairly clear, appears to dip at edge but probably 1 just the cut very difficult slide, lot of lines all very similar, would 1 probably discard this one or estimate June similar mid-line between lines 1 and 2 but no dip, 1.2 structure fairly clear 101

2.8 3.9

2.1? 2.4? 2.2 2.1

2.1

2.6

2.2

2.5

2.8

2

2.2

2 2

2.2

1.5

2.6

2

2.6

1.7

APPENDIX 1 C.8.H.11.R

14-Oct-96

3

C.10.H.12.L

10-Dec-96

3

C.10.H.17.L

10-Dec-96

1

C.11.H.13.L C.11.H.23.L

22-Jan-97 22-Jan-97

2? 2

Site J C.2.J.11.L C.2.J.11.R.a

09-Apr-96 09-Apr-96

2 2

C.2.J.11.R.b

09-Apr-96

?

C.2.J.12.L

09-Apr-96 3?4?

C.2.J.12.R.a

09-Apr-96 3?4?

C.2.J.12.R.b

09-Apr-96 3?4?

C.2.J.16.L

09-Apr-96

4

C.2.J.16.R.a

09-Apr-96

5

C.2.J.16.R.b

09-Apr-96

5

C.3.J.15.L

22-Apr-96

?

C.3.J.15.R.a C.3.J.15.R.b

22-Apr-96 ? 22-Apr-96 4?5?

C.3.J.16.L

22-Apr-96

3

C.3.J.16.R.a

22-Apr-96

4

C.3.J.16.R.b

22-Apr-96

4

C.3.J.18.L

22-Apr-96

C.3.J.18.R.a C.3.J.18.R.b

22-Apr-96 22-Apr-96

C.12.J.9.L

27-Feb-97

3

C.12.J.9.R.a

27-Feb-97

3

C.12.J.9.R.b

27-Feb-97

3?

C.12.J.11.L 27-Feb-97 C.12.J.11.R.a 27-Feb-97

? 3?

C.12.J.11.R.b 27-Feb-97

4?

C.12.J.14.L 27-Feb-97 C.12.J.14.R.a 27-Feb-97

2 3?

C.12.J.14.R.b 27-Feb-97

3?

some disturbance and unclear as to which line is the second although probably the one with dip lines fairly clear with mid-lines, no dipping, would perhaps be difficult to estimate month not cut through to tip so probably older, triangle and clear structure useless, thin slide, dark patch near edge lines fairly clear, edge dipping, measurements could be deceiving

1.6

3

2.5

1.5

2.6

4

? 1.2

1.8

lines distinctive, dip and triangle, line about to form measurements slightly different from above, still can see triangle and dip, line about to form re-make, very different, lines not at all so obvious, measurements different, line about to form still many disturbance lines, one line forming on edge but hard to distinguish from others as above, disturbance lines much thicker, slightly darker annual lines, one forming on edge very similar to above, line clearly forming on edge with dip and triangle one line forming on edge, very difficult however as many disturbance lines, all very similar vaguely similar to above although can identify 2 more lines, have to examine structure here lines 2 and 3 look different here, but this slide very thin, looking at structure more than lines would have to discard this slide, far too much disturbance, only indicator is little triangle same as above strangely the annual lines seem to stand out more in this re-make, especially at ligostracum junction very disturbed, from structure can identify 3 lines and one seems to be forming on edge can also see changes in colour and structure in the ligostracum, appears to be another line here similar but more compacted, lot more taken off in remake as lines on more of a slant slide too thin, portion missing from growing edge, would be discarded discard, too unclear due to some stage in thin sectioning process this remake has also got cracks through it lot of disturbance but relatively clear, edge dipping, looked more at structure than lines lines similar, one about to form on edge, dip and triangle slide broken, lot more taken off, completely distorted picture, see measurements discard, very disturbed, slightly clearer, subtle changes in colour, very disturbed colouring slightly more obvious, also appears to be another line less disturbed, only mid-lines, little triangle and dip little different, appears to have 3 lines, edge dipping down measurements slightly different, lines fairly clear

2.5 2.6

2.4 2.1

2.6

1.9

2.1

2.3 2.7?

102

3

2

2.1

2

2

2

1.8

2.2

2

2.5

2.2

2.7

2

2

2.1

1.9

2.7

2.1

? ? 2?

1.9? 1.4? 2.2?

2.2

2.7

2.5

2.2

2.5

1.9

2.2

2.2

2

1.6

1.5

1.9

2.3

2.2

1.8

2

2

1

2.5

1.7

? 2.2

2.8

2

2

2.5

1.8

1.8 1.7

2.5 2

2.8

1.6

1.4

2.5

? ? ?

1.5

APPENDIX 1 C.13.J.15.L

05-Mar-97

?

C.13.J.15.R

05-Mar-97

4?

C.13.J.20.L C.13.J.20.R

05-Mar-97 05-Mar-97

5? 5?

C.13.J.21.L

05-Mar-97

2?

C.13.J.21.R.a 05-Mar-97

3?

C.13.J.21.R.b 05-Mar-97

3

too thick to see anything clearly, many disturbance lines and edge slightly broken appears to be 4 lines but not absolutely sure, lot of disturbance line appears to be forming on edge, mid-lines measurements very different due to cut and grind, dipping on edge, line about to form slide quite thick and mid-lines are confusing, growing edge a little broken from colour and structure there appear to be 3 lines, mid-lines similar to annual lines again difficult, much more removed from this remake, measurements smaller

? 1.9

1.8

2

2.2

1.5 1.5

1.7 1.4

1.4 1.2

1.7 1.3

2

2.5

1.9

1.4

2

1.7

1.5

1.6

2.7

Southampton Identity

Date

Age

Site B S.1.B.6.L

04-Dec-95

2

S.3.B.8.L

04-Mar-96

3

S.4.B.2.L

25-Apr-96

?

S.5.B.10.R

28-May-96

?

S.6.B.10.L

24-Jun-96

2

S.7.B.6.L

28-Jul-96

1

S.8.B.5.R

19-Aug-96

3?

S.9.B.10.R

30-Sep-96

2

S.10.B.11.R

25-Nov-96

2

S.11.B.9.L

16-Dec-96

3?

S.12.B.7.R

20-Jan-97

1

S.13.B.13.R

24-Mar-97

4

Site C S.1.C.6.L

04-Dec-95

2

S.2.C.5.L

13-Feb-96

2

S.3.C.6.L

04-Mar-96

2?

S.4.C.7.L

25-Apr-96

3

Notes

Years 0-1

1-2

2 clear lines, mid-lines, edge dipping and little triangle lines fairly clear, third line seen more from changes in structure, some mid-lines, triangle and dips would have to discard this one, great deal of disturbance, line just about to form? line right at edge but so much disturbance and too much ground away, have to discard would probably get this one wrong, mid-lines look a bit like annual ones, but thicker quite a lot of growth for a July shell, looks like edge is dipping so could be deceiving some disturbance, not altogether clear, measurements a little deceiving 2 probable lines but not very clear, dipping at edge a little 2 lines seen as fairly clear breaks, mid-lines just dark lines, no dipping very difficult, lot of disturbance, structure no help, dipping and triangle on edge very difficult, one line fairly clear, see more from structural changes, some dipping and triangle measurements strange here, line just formed on edge, triangle and dip also, much disturbance

1.9

2.2

1.2

1.4

bad slide, line looks about to form, dip and triangle, last line clearer than second very difficult, lot of disturbance lines, edge dipping and about to form a line lines not particularly clear, edge dipping and looks like about to form a line, measurements odd thick slide but can see annual lines as clear breaks in structure, mid-lines darker, line on edge

103

2-3

2

? ? 0.4 1.8 1.1 0.7

3

2.6

0.8

2.5

2.2

2.8

1.2

2

2.4

1.1

1.4

1.9

1.9

1.8

2.1

2.5

3

2

2.4

2.1

2.6

3-4 4-5

APPENDIX 1 S.5.C.6.R S.6.C.6.R S.7.C.9.L S.8.C.4.L S.9.C.12.L S.10.C.8.R S.11.C.7.R S.12.C.8.L S.13.C.14.L

28-May-96 2 lines fairly clear, last line very near edge 24-Jun-96 2?3? cut on a slant, line very close to edge, mid-line a little like annual lines 28-Jul-96 2?3? 2 obvious lines, clear breaks with dips and ligo. lines, structural patterning 19-Aug-96 3 lot of disturbance, measurements a little odd, edge looks like starting to dip 30-Sep-96 2 lines clearer under low mag. with stronger dips, disturbance but structural patterning 25-Nov-96 3 slide too thick, looks like cut at an angle, measurements a bit small 16-Dec-96 2? colour and patterning of structure help here, no triangle or dip yet 20-Jan-97 3? not at all clear, lot of disturbance lines, edge is dipping, there is a little triangle 24-Mar-97 2 triangle and edge is dipping over, looks like line is about to form, structure and dips define lines

Site D S.2.D.6.R

13-Feb-96

2?

S.3.D.9.R

04-Mar-96

3?

S.3.D.10.R

04-Mar-96

4

S.3.D.12.R

04-Mar-96

2

S.3.D.13.R

04-Mar-96

?

S.4.D.6.L

25-Apr-96

3

S.5.D.6.R

28-May-96

2

S.5.D.7.R

28-May-96

4

S.6.D.6.L

24-Jun-96

?

S.6.D.8.R

24-Jun-96

?

S.6.D.10.R

24-Jun-96

2

S.7.D.6.L

28-Jul-96

3

S.7.D.8.R

28-Jul-96

4

Site E S.3.E.11.L

04-Mar-96

5

S.3.E.12.R

04-Mar-96

2

S.3.E.14.L

04-Mar-96

1

S.3.E.18.R

04-Mar-96

1

S.4.E.12.L S.4.E.14.L

25-Apr-96 25-Apr-96

1

S.4.E.15.L

25-Apr-96

2?

0.3 0.4

2.8 3

0.6

1.9

0.9

1.4

2

3.3

0.7

1.3

0.9

1.5

1.7

1.8

1.2

1.6

neither of lines clear, area of growing edge too thick, 0.9 cut slanting, conchiolin down edge cut on a slant, lot of disturbance, looks like line is 1.5 about to form in edge, line in ligostracum all lines quite clear from disturbance lines, colour and 1.9 structure help, line about to form, dipping line is about to form, dip and structure gets lighter, 1.3 other lines not clear and shell has split totally useless, 2 heavy lines of conchiolin on edge, ? cut too far to one side or over-ground some disturbance in last year, lines fairly clear, line 1.4 may be forming, edge lighter bad slide, cut wrong or ground badly, on a slant, dip 0.05 and line near edge, line in ligostracum clear lines evenly spaced, some disturbance lines, 1.5 last line right on edge absolutely useless, too thin, cut or over-ground ? badly, can just see a line on edge useless, too much removed or cut badly, lot of ? disturbance and conchiolin lines throughout very difficult, 2 lines visible, lot of disturbance and 0.2 conchiolin lines lines fairly clear, one large conchiolin, one line near 0.35 edge structure and colour useful, lot of disturbance and 0.6 conchiolin, quite difficult

1.4

hard to get month as edge broken, has thick area full of disturbance lines, measurements odd line about to form, triangle and dipping, colour and structure help, 3 thick conchiolin patterned one line not very clear, structure and colour, also mid-line, line about to form, ligo. and dip one line although mid-line could be mistaken, dip and triangle on edge over-ground looks like one line and mid-line, line about to form, triangle and dip either line has formed near edge or last line is a 104

3.4

1.7

1.8

2.5

2.5

1.5

2

2.2

2.1

2.1

3.4 1.5

1.4

2 1.5

1.7

1.3

1.3

2.1

?

4

2.7

2.2 2.2

1.6

1.7

2.8 2.4 ? 2.5 0.2

1.8

APPENDIX 1

S.4.E.22.L

25-Apr-96

2

S.5.E.10.R

28-May-96

?

S.5.E.14.R

28-May-96

2

S.5.E.16.L

28-May-96

2

S.5.E.17.L

28-May-96

2

S.6.E.9.R

24-Jun-96

2?

S.6.E.10.L

24-Jun-96

3?

S.6.E.11.L

24-Jun-96

3?

S.6.E.15.L

24-Jun-96

2

Site F S.1.F.5.L S.1.F.6.R

04-Dec-95 04-Dec-95

S.2.F.1.La

13-Feb-96

S.2.F.1.Lb

13-Feb-96

S.2.F.2.L S.2.F.2.R

13-Feb-96 13-Feb-96

S.2.F.3.L

13-Feb-96

S.2.F.3.R

13-Feb-96

S.2.F.4.L S.2.F.4.R

13-Feb-96 13-Feb-96

S.2.F.5.L S.2.F.5.R S.2.F.6.L

13-Feb-96 13-Feb-96 13-Feb-96

S.2.F.6.R

13-Feb-96

S.2.F.7.L

13-Feb-96

S.2.F.7.R

13-Feb-96

S.2.F.8.L

13-Feb-96

S.2.F.8.R

13-Feb-96

S.3.F.6.L

04-Mar-96

S.3.F.8.L

04-Mar-96

S.3.F.8.R

04-Mar-96

S.4.F.4.L

25-Apr-96

disturbance and line is about to form very thick disturbance line midway between last line and edge, annual lines fairly clear, dip cut badly on a slant, line very near edge, dense structure hard to interpret even though thin slide not particularly clear, line very near edge, some disturbance, not much structure or colour change lines clearer at low mag. some disturbance and midlines, line possibly at edge 2 fairly clear lines, couple of disturbance lines, dip and line near edge very difficult as cut on a slant, last line very near edge last line clear, others not so sure about, structural changes under low mag. possibly 3 lines, third seen as more of a structural change 2 lines, some disturbance in between, clear dips at junction though for annual lines

thin section peeled off slide 3 measurements a little odd, lines fairly clear but some disturbance, edge dipping, little triangle 4 first cut, lines varying degrees of clearness, not much evidence for dipping at edge 3 bit different to above slide, lines not clear and only appear to be 3 lines, lot of disturbance useless, at least 10 conchiolin lines discard, most of it ground out, ground by hand and also had large moisture content initially 2 very thin slide, measurements a bit misleading, dipping at edge and looks like line about to form 3 this side a lot clearer, 3 lines, dipping at edge and little triangle discarded 4 fairly clear lines, dips in junction, edge dips and little triangle, measurements no help cracked and therefore discarded useless, bad cut on a slant and bond not worked well 3? very difficult, hand prepared and ligo ground out, lines not very clear, structure helpful edge dips useless, slide too thick and ground to a slant, bears no resemblance to the above 3 quite clear lines, good evidence at junction, edge dipping quite a lot, measurements no help 2 fairly useless, ground to a slant, can only identify 2 lines 2? looks like a line is forming on edge, dipping and structure gets lighter, lines clear 3 appear to be 3 lines, prob. the cut, clearer than above and definitely about to form a line 2 fairly clear lines, some disturbance, dipping edge, looks like line is forming 2 quite clear, structure very clear, edge slightly broken but looks like line is forming 1?2? can only see one definite line, edge slightly broken, dip and little triangle 4 lines clear, some disturbance lines, line forming on 105

1.9

2

? 0.2

2

1.6 0.1

2

0.2

1.4

0.2

1.2

1.6

0.3

1.5

2.5

0.2

2.6

? ? 1

1.4

1

1.2

1.5

1.5

2.4

? ? 0.8

1.8

1.3

2

2.2

? 1.6

2.2

1.4

? ? 1.2

2.2

1.9

2.2

2.7

? 1.3 ? 1.7

2.5

1.2

2.2

1.5

? 2

1.9

1.6 0.8

1.9

2.9

2.3

APPENDIX 1

S.4.F.4.R S.4.F.5.L S.4.F.5.R S.5.F.5.L S.5.F.5.R S.5.F.6.L S.5.F.6.R S.5.F.7.L S.5.F.7.R S.5.F.8.L S.5.F.8.R S.6.F.5.L S.6.F.6.L S.6.F.7.L S.6.F.7.R S.7.F.8.L S.7.F.9.L S.7.F.10.L S.7.F.10.R S.7.F.11.L S.7.F.11.R S.7.F.12.L S.7.F.13.L S.7.F.13.R S.8.F.6.L S.8.F.6.R S.8.F.7.L S.8.F.7.R S.8.F.9.L S.8.F.9.R

edge, little triangle different to above, over-ground and lot of 1.5 disturbance, edge dipping a lot, looks like line is forming 25-Apr-96 3 quite a lot of structural changes, very grey in last 1.2 year, measurements a little odd, dipping edge 25-Apr-96 ? completely useless, really over-ground or cut badly ? on a bad slant 28-May-96 2?3? possibly 3 lines, slide quite thick but first 2 lines 0.1 clear, some disturbance 28-May-96 4? very different to above, looks more like 4 lines, much 0.1 clearer, better half and thinner 28-May-96 broken during thin sectioning ? 28-May-96 ? useless, can not see any lines, quite thick slide, edge ? looks a little broken, disturbance 28-May-96 2 quite thick but 2 clear lines under low mag. may have 0.1 been cut on angle 28-May-96 2? not particularly useful, cut on angle, too much of a 0.3 slant, can see 2 lines but structure messy 28-May-96 4 line just formed on edge, others fairly clear, some 1.2 mid-lines, cut on a bit of a slant possibly 28-May-96 4 slightly different measurements, may be the cut, line 1.2 on edge, big dip down, lighter around lines 24-Jun-96 cut off badly during thin sectioning process, ? discarded 24-Jun-96 4 too thick, last line very obvious, others can see from 0.25 changes in the structure 24-Jun-96 5? not very clear, some bad scratches and quite thin, 0.3 last line clearest, others fairly sure 24-Jun-96 5?6? not quite sure how old this one is, lot of lines and 0.1 disturbance, 5-6 is only 0.8mms 28-Jul-96 useless, looks like line is forming on edge but lot of 0.3? disturbance, another line near edge 28-Jul-96 useless, line on edge but may be disturbance line, ? many others and break in shell 28-Jul-96 bad bond, discarded during thin sectioning process ? 28-Jul-96 useless, cannot see any lines, lot of disturbance ? including many conchiolin lines 28-Jul-96 3 fairly clear lines with dips in junction, under high 0.3 mag. seen as clear breaks 28-Jul-96 3 fairly similar to above, split down back and lot of 0.2 conchiolin lines, on bit more of a slant 28-Jul-96 2 last line fairly clear, second not so much, quite a lot 0.4 of conchiolin, couple of mid-lines 28-Jul-96 2? very deceiving, can hardly see lines at all, last is dark 0.3 line, wrongly looks like line is about to form 28-Jul-96 2? cut on a bad slant, very difficult, lines not particularly 0.6 clear 19-Aug-96 2 second line clearer than last, mid-lines, edge could 1.1 be misleading 19-Aug-96 2?3? fairly similar although measurements different and 0.8 possibly another line, disturbance 19-Aug-96 3 fairly clear from colour and structure, dips in 0.15 ligostracum, not much disturbance 19-Aug-96 3 very similar to above, 3 clear lines, some conchiolin 0.6 at oldest end, ground to a bit of a slant 19-Aug-96 3 structure very homogenous, 3 lines not very well 0.5 defined 19-Aug-96 useless, ground to a slant, not very clear ? 25-Apr-96

2

106

1.8 2.8

1.7

2.2 1.8

1.5

1.3

2.3 2 1.9

2.8

2.4

1.4

1.8

1.6

2.3

1.2

1.6

1.2

0.7

1.5

1.4 1.3

1

1.5

0.7

1

2.6 1.2 1.2 2.6 1.4

?

1.5

2

1.4

2

1.5

1.6

2

APPENDIX 1 S.8.F.10.L S.8.F.10.R S.9.F.4.L S.9.F.4.R S.9.F.5.L S.9.F.5.R S.10.F.5.L S.10.F.5.R S.10.F.6.L S.10.F.6.R S.10.F.7.L S.10.F.7.L.r S.10.F.7.R S.11.F.6.L S.11.F.6.R S.11.F.7.L S.11.F.8.L S.12.F.6.L S.12.F.6.R S.12.F.7.L S.12.F.7.R S.12.F.8.L S.12.F.8.R S.12.F.9.L S.12.F.9.R S.12.F.9.R.r S.12.F.10.L S.12.F.10.R S.13.F.13.L S.13.F.13.R S.13.F.15.L S.13.F.15.R

19-Aug-96

useless, far too many conchiolin lines, break in structure may be a line 19-Aug-96 useless, same as above 30-Sep-96 5? lines fairly clear except 2, only evidence is dip in junction, not much disturbance 30-Sep-96 6? looks like there may be an extra line at the back, 3.2 mm from 5, line 2 still not very clear 30-Sep-96 3 very clear lines, one mid-line, hardly any conchiolin, ligostracum lines also 30-Sep-96 3 very thin slide, difficult to see much, line 3 very hard to see and ligostracum broken also 25-Nov-96 2 fairly clear lines, little triangle and starting to dip a little 25-Nov-96 3? appears to be 3 lines here, some mid-lines but annual lines have dips in junction, triangle and dip 25-Nov-96 4 all lines very clear, very thin slide, dipping and little triangle at edge 25-Nov-96 4 not as clear as above, lines more compacted, edge not clear, dips a little, conchiolin obscuring 25-Nov-96 cut off badly during sectioning and re-make attempted 25-Nov-96 3? 3 fairly clear lines though not evenly spaced, edge dipping, some disturbance lines 25-Nov-96 3 similar to above, starting to dip a little, lines fairly clear but similar to disturbance lines 16-Dec-96 4 disturbance lines are similar to annual ones, edge dipping over 16-Dec-96 4?5? very similar to above, strange measurements, quite thick and dark slide, edge dipping a little 16-Dec-96 1 very dark and looks like air has got into the bond but it has not, only 1 line not very clear 16-Dec-96 useless, edge broken and lot of conchiolin lines 20-Jan-97 5 looks like there are 5 lines, not spaced very far apart, edge dipping and little triangle, mid-lines 20-Jan-97 useless, too much removed grinding, cannot see individual lines, crowded together near edge 20-Jan-97 4 cut on a bit of a slant, dipping edge but no triangle 20-Jan-97 5 possibly 5 lines, possible as may be cut on skew, fairly clear and dips in ligo., edge dipping 20-Jan-97 2 lines seen from changes in colour and structure, little triangle, dipping at edge, line forming? 20-Jan-97 2? very difficult to read, measurements very different, seems to be on a slant, hardly any dip 20-Jan-97 2 lines seen from changes in colour and structure, edge dipping a little and triangle, mid-lines 20-Jan-97 cut off badly during thin sectioning process, re-make attempted 20-Jan-97 2 looks very different to L side, big bulge at edge from grinding too much 20-Jan-97 3 not very clear but good dip at edge and little triangle 20-Jan-97 3 fairly similar, lines a bit clearer, better dips, may be more on a slant, edge dipping 24-Mar-97 4 not sure about these lines, conchiolin obscuring second, large one on edge also, dip and triangle 24-Mar-97 5 another line here, not very clear, conchiolin on edge, not dipping much 24-Mar-97 1? edge dipping right over, looks like line is forming on edge 24-Mar-97 3 quite different to above, line near edge not on it, 107

? ? 0.6

1.9

2.3

0.8

1.9

1.9

0.8

2

3.2

0.8

1.5

2.2

1.4

2.7

1.2

2.4 3.8?

0.6

0.7

1.7

1.3

0.3

0.6

1.3

0.6

1.2

1.1

2.3

1.2

1

1.9

0.5

1.7

0.7

1.2

0.7

0.8

1

0.6

1.2

1.2

1.2 1.4

0.9 0.8

1.4 1

2 1.6

2.4 2.1

1.4

1.6

0.3

1.8

1.7

2

1.4 2.3 1

1.6

?

2.5 ? 0.9 ?

? 2

2

1.4 1.2

1.6 1.3

2.3 2

1.4

1.7

1.2

1.5

1.5

1

2.4

2.2

3.2 0.3

1.5 1.5 2.7

APPENDIX 1

S.13.F.16.L S.13.F.16.R S.13.F.17.L S.13.F.17.R S.13.F.18.L S.13.F.18.R S.13.F.19.L S.13.F.19.L.r S.13.F.19.R S.13.F.20.L S.13.F.20.R S.13.F.21.L S.13.F.21.R

possibly 2 others not so clear, mid-lines also, edge dipping, looks like line is forming 24-Mar-97 3 not clear but maybe 3 lines, dip on edge but looks like line has just formed 24-Mar-97 1? lot of disturbance, looks like line is forming on edge, otherwise very unclear 24-Mar-97 ? very over-ground thin slide, line does not match up to one above, does look like one on edge 24-Mar-97 3 quite a lot of disturbance, lines fairly clear and looks like line forming right on edge 24-Mar-97 3?4? lot of disturbance but lines are relatively clear, looks like one right on edge 24-Mar-97 cut off badly during thin sectioning process so remake attempted 24-Mar-97 1 not very clear, line identified more from colour and structure changes, looks like line is on edge 24-Mar-97 2? very different to above, appears to be 2 lines, no evidence for one at edge, but is dip and triangle 24-Mar-97 2? not clear, very dark, looks like 2 lines, does look like line has formed on edge 24-Mar-97 1?2? very dark on edge so hard to say much, possible break at second line, bit useless 24-Mar-97 ? cannot see much, under high mag. line formed at edge, otherwise no other lines visible 24-Mar-97 1 thick slide and air in bond, line very clear break, looks like one may be on edge 24-Mar-97

2

Site H S.1.H.7.L

04-Dec-95

2

S.2.H.9.L

13-Feb-96

1

S.3.H.12.R

04-Mar-96

3

S.4.H.14.L

25-Apr-96

2

S.5.H.7.L

28-May-96

2

S.6.H.7.R

24-Jun-96

2

S.7.H.6.R

28-Jul-96

2

S.8.H.5.R

19-Aug-96

3

S.9.H.13R S.10.H.9.R

30-Sep-96 25-Nov-96

3

S.11.H.9.R

16-Dec-96

1

S.12.H.10.R

20-Jan-97

1

S.13.H.8.R

24-Mar-97

4

Site I S.1.I.12.L

04-Dec-95

2

S.2.I.13.L

13-Feb-96

?

1.8

1.9

1.5

1.1

1.4

1.1

1.2

1.2

1

1.4

1.3

1.6 1.3

? 1.9 1.2

2.4

1.2

2.6

1.5

1.7

? 1.9

2 clear lines, measurements not much help, no obvious dipping or triangle line very clear, mid-line and conchiolin line as well, edge dipping and triangle, line about to form second line not so clear, may be mid-line, one forming on edge, dipping and triangle line right on edge, other fairly clear, structural changes, mid-line and a little disturbance lines very obvious, structural changes, line formed very near edge 2 clear lines, a lot of conchiolin in the first years growth fairly clear lines, line in ligostracum also, large band between 1 and 2 a lot of disturbance, measurements comparatively smaller than others from here useless, cut on a slant and quite thick lines 1 and 3 clearer, 2 more structural changes and break in ligo. not much growth for November not very good as cut on a slant, there is one line but nothing in past years to compare with 1 lines, possibly another right at back edge, quite clear, edge beginning to dip and small triangle line obviously forming on edge, big dip and little triangle, measurements bit odd, lines very clear

2.5

2 lines, looks like line is forming on edge, no dip or triangle, lines fairly clear, some mid-lines useless, lots of conchiolin lines all way through, 108

1.5

3 1.1

1.5

3 0.1

3.5

0.5

2.4

1.1

3.3

0.5

1.9

24

? 0.5

2.2

2.4

1.5

3.5

3.5

1.5

2.1

1 1.8

?

APPENDIX 1

S.3.I.19.R S.4.I.12.R S.5.I.10.R S.6.I.5.L S.7.I.10.L S.8.I.6.L S.9.I.9.R S.10.I.8.L S.11.I.10.L

breaks in structure and too thick, line forming? 2 fairly clear lines, measurements no help, little triangle on edge, prob. assess earlier in year 25-Apr-96 1?2? edge a little broken, may be a line at point of break, other line clear 28-May-96 3 last line right on edge, dipping also, others clear big structural and colour changes, disturbance 24-Jun-96 1? 1 line near edge, clear break, rest of shell hard to interpret, cut on a slant 28-Jul-96 2 both lines clear, mid-line between edge and last line, perhaps would estimate later in year 19-Aug-96 3 lines very clear and have mid-lines, triangle at edge but not enough growth for full year 30-Sep-96 1? very difficult, change in colour indicates line but no others visible, little thick and conchiolin 25-Nov-96 1 can only see 1 line, mid-line, could mistake dip near edge as line but no evidence further down 16-Dec-96 2 2 lines with structural changes in bands, edge dipping 20-Jan-97 4 all lines fairly clear, few faint mid-lines, looks like line about to form on edge, dips down a lot 24-Mar-97 2 lines very clear, especially under low mag., not dipping but rising, measurements no help 04-Mar-96

2

1.4

3.2

1.6 1.5

2

0.2 0.5

2.3

0.7

2.1

2.1

0.6 1.8 1.5

1.5

0.9

1.5

2.1

3

very clear lines with mid-lines between, triangle and structure indicate later in year 13-Feb-96 ? very difficult, bit too thick and quite disturbed, does have triangle at edge and a dip 04-Mar-96 4? lines very clear and structure well patterned, dipping down at edge and line in ligo. 25-Apr-96 3 2 lines, and one appears to be forming one edge, dip and ligo. lines, lot of disturbance 28-May-96 4 line near edge, patterning of structure and lines quite clear 24-Jun-96 4+ very unsure of age, lot of lines but also a lot of conchiolin, structure quite dark, line near edge 28-Jul-96 2 quite a lot of disturbance and thick, only appear to be 2 lines 28-Jul-96 2?3? difficult one, measurements no help, may be a line nearer edge 19-Aug-96 2 clear and patterned structure, may be another line further back 30-Sep-96 2 clear lines with mid-lines between, dipping of edge starting 25-Nov-96 2 half of shell destroyed, not much growth between lines, might estimate earlier in year 16-Dec-96 3? lines not very clear, some false ones also, some dipping at edge, some conchiolin lines 20-Jan-97 3? slide too thick, lot of disturbance, ligo. no help, beginning to dip at edge and has little triangle 24-Mar-97 2 some dipping at edge and looks like line is about to form on the edge

1.5

2.7

1.7

0.9

1.5

1.2

2.4

1.9

1.8

0.1

1.6

1.9

2

0.2

1.1

1.3

0.9

0.7

3.3

1.2

1.8

0.8

1.8

0.9

2.1

0.6

1.2

2.1

1.2

2.4

1.1

2.3

1.4

0.9

2.5

Site K S.1.K.8.R

04-Dec-95

2

1.5

2.4

S.2.K.11.R

13-Feb-96

2?

S.12.I.12.L S.13.I.13.L

Site J S.1.J.8.L S.2.J.5.L S.3.J.13.R S.4.J.8.R S.5.J.7.R S.6.J.6.L S.7.J.11.R S.7.J.12.L S.8.J.8.R S.9.J.9.L S.10.J.6.L S.11.J.9.R S.12.J.9.L S.13.J.14.R

04-Dec-95

3

quite a thick slide but lines stand out well, edge dipping down but no triangle or ligo. line cut on a slant so measurements no help, last line on an angle, little triangle on edge, bit of a dip 109

1.7

2.2

?

?

APPENDIX 1 S.3.K.14.R

04-Mar-96

2

S.4.K.9.R

25-Apr-96

3

S.5.K.8.R

28-May-96

3

S.6.K.7.R S.7.K.5.L

24-Jun-96 28-Jul-96

1? 2

S.7.K.5.R

28-Jul-96

3

S.7.K.6.L

28-Jul-96

?

S.7.K.6.R

28-Jul-96

7?

S.7.K.7.L

28-Jul-96

7?

S.7.K.7.R

28-Jul-96

?

S.7.K.8.L

28-Jul-96

2

S.8.K.?.R S.9.K.5.R

19-Aug-96 30-Sep-96

3 3

S.10.K.11.R S.11.K.6.L

25-Nov-96 16-Dec-96

1? 2?

S.12.K.11.L

20-Jan-97

1?

S.13.K.8.L

24-Mar-97

3

Site L S.1.L.10.R

04-Dec-95

3

S.2.L.6.R

13-Feb-96

5

S.3.L.10.L

04-Mar-96

2?

S.4.L.6.L

25-Apr-96

?

S.5.L.6.L

28-May-96

5

S.6.L.5.L

24-Jun-96

2?

S.7.L.10.R S.8.L.9.R

28-Jul-96 19-Aug-96

4 4

S.9.L.7.R

30-Sep-96

2

S.10.L.6.R

25-Nov-96

3?

S.11.L.3.L

16-Dec-96

2?

S.12.L.8.L

20-Jan-97

2

S.13.L.10.R

24-Mar-97

2?

bit too thick and on a slant, measurements no use, hard to tell if dipping and no triangle some disturbance and large conchiolin line and break in last band, dip at edge either cut badly or over-ground, lines clear, one just by the edge, lot of disturbance lines fairly useless, too thick, no line near edge measurements fairly helpful, quite a lot of conchiolin in first year, lines fairly clear line clear with dips and ligo. lines, measurements decrease edge slightly broken and a lot of lines, lot of conchiolin further back old shell, possibly 7 lines all quite clear, edge a bit broken, 5-6: 1.5mms, 6-7: 1.7 mm another old shell, all lines clear, 5-6: 1.5mms, 6-7: 1.7mms useless, cut too far or over-ground completely, some lines but not clear may be 3 lines, one right at back end, may have been cut on a slant, lines fairly clear 3 lines unevenly spaced, last band is relatively short last band not very wide for September, was cut on a bit of a slant cut on a slant, line fairly clear difficult, may be 2 lines although only last is clear, second seen more from ligo. break, edge dips bonded very badly, lot of air bubbles, dipping at edge and little triangle not very clear but is dipping at edge and little triangle present

measurements no help, dipping and triangle present, some conchiolin 5 lines identified mainly from colour and structural changes, lot of disturbance last line clear break in structure, does not dip much at edge, looks like line may be forming very difficult as not ground completely to shell, some missing, line forming on edge lines very clear, some mid-lines, colour and structure patterns 2 lines, possibly more but not clear, some shell removed during thin sectioning process 4 lines quite faint, seen under higher magnification clear under higher magnification, some mid-lines and conchiolin very difficult as hard to see junction between shell matrix and ligo. conchiolin line on edge also possibly 3 lines although measurements look unlikely, other disturbance lines very difficult as a lot of disturbance, identified lines from changes in colour, last year browner quite disturbed with conchiolin lines and mid-lines, triangle and dip at edge quite a lot of disturbance, 2 very large conchiolin lines, line about to form on edge, dip, triangle

110

? ?

2.9

2.5

1

2

? 0.6

2

0.8

1.4

2.4

0.7

1

1.4

0.3

0.6

0.9

? 1.3 0.8 1

1

? 0.9

3.5

0.8 0.5

1.4 1

1.7 0.6

1.4

3.4 1.8

2 1.3

1.5

1.2

1.3

2

1.8

1.8

2

2

2.1

2

2.1 2.2

? 0.2

2.2

0.3

1.4

0.5 0.8

1.4 2

1

2.4

1.8

2

1.7

2.1

1.5

1.4

2

2.5

2.2

1.6

1.4 1

1.9 1.7

1.4

2

APPENDIX 1

Truro Identity

Date

Age

Notes

Years 0-1

Helford River T.1.U.8.R T.1.U.11.L

T.8.V.4.R T.8.V.4.R

bit obscure, line about to form, edge dipping a little 3 big growth disturbance in structure, line hard to pick out, 2.6 junction topography no help 23-Mar-96 1?2? one line goes right up to junction, quite a lot of other lines 2.6 and disturbance, dipping at edge 23-Mar-96 2 appears to be 2 lines, slightly broken at edge, dips over a 2.2 little, line 1 coincides with a dip 23-Mar-96 2 difficult one, line 1 fairly clear, line 2 probable, dipping a 1.4 little at edge 23-Apr-96 2 line formed near edge, not classic but definite breaks in 0.2 growth 23-Apr-96 2 one line formed near edge, other line unclear but possible 0.1 from changes in colour and structure 23-Apr-96 broken during thin sectioning ? 23-Apr-96 very badly made slide ? 23-Apr-96 2 line very near edge, line 2 clear at some points in 0.05 structure, clear line through grey material, dips 02-Jun-96 1 no obvious recent line, edge is dipping and triangle is 1.8 evident in ligostracum, poss. just forming 02-Jun-96 2?3? very difficult, 2 lines very clear but under high mag 1.4 another possible near no. 2, line near edge? 02-Jun-96 broken during thin sectioning ? 02-Jun-96 bad bond so discarded ? 02-Jun-96 1?2? line near edge but not particularly classic, another 0.2 possible 02-Jun-96 2 very difficult, false lines but these are wider than the 0.4 annual lines 02-Jun-96 2 1 clear line defined by dark edges, other not so obvious, 0.3 slide bit thick, some disturbance 29-Jul-96 3? fairly clear, lines more classic, good patterning, darker 0.4 lines just after, spawning? 29-Jul-96 2 both lines clear, defined by darker lines especially at 0.4 margin, some disturbance 29-Jul-96 2 neither lines particularly obvious, not much indication at 0.8 junction, clearer under low mag. 29-Jul-96 2 lines fairly clear, may have been over-ground, disturbance 0.3 lines 29-Jul-96 2 lines fairly clear, disturbance lines do not extend up to the 0.4 junction 04-Oct-96 3 appears to be 3 lines occur with dips in junction, others 0.9 disturbance lines 04-Oct-96 1 difficult as several browner disturbance lines, none very 1.2 clear, 04-Oct-96 2 line 1 clear under low mag, occurs with dip in junction, 2 is 1 a possible but also disturbance lines 04-Oct-96 broken during thin sectioning ? 04-Oct-96 bad bond so discarded ?

Site O T.2.O.6.L

22-Apr-96

2

T.2.O.7.R

22-Apr-96

2?

T.1.U.12.R T.1.V.7.R T.1.W.10.R T.2.U.7.L T.2.U.8.L T.2.W.7.L T.2.W.7.L T.2.W.10.L T.4.U.9.L T.4.U.8.L T.4.U.10.L T.4.U.10.L T.4.U.11.L T.4.V.13.L T.4.W.12.L T.5.U.6.R T.5.U.7.L T.5.U.9.L T.5.V.7.L T.5.W.10.L T.8.U.6.R T.8.U.5.L T.8.V.5.R

23-Mar-96 23-Mar-96

1-2 2-3 3-4

1 1

2 lines not particularly clear except at the junction, line 1 just formed, very near the edge last line very obvious near edge, dip in junction, slide 111

0.2 0.2

1.5 2 2.6

1.9

1.4

1.7 2 1.7 2.8 2.1 2.1 2.6 3 2.1

3.5

2.2

2

APPENDIX 1

T.2.O.8.R T.2.O.9.L T.3.O.5.L T.3.O.7.L T.3.O.8.L T.4.O.7.L T.4.O.8.L T.4.O.10.R T.4.O.11.L T.5.O.4.L T.7.O.6.L T.7.O.7.L T.7.O.9.R T.7.O.10.R T.8.O.8.R T.8.O.10.R T.8.O.11.R T.8.O.13.L T.9.O.6.L T.9.O.6.L T.9.O.8.R T.9.O.9.R T.9.0.10.R T.10.O.6.L T.10.O.7.R T.10.O.9.R T.10.O.10.R T.11.O.5.R. T.12.O.6.R T.12.O.8.R

perhaps too thick, prob. another line slide very thin, air under resin, 2 lines visible under low magnification 22-Apr-96 3 second line actually a break but likely to be down line, other two clear at junction 22-May-96 3 slide too thick, three possible lines, some dip and definition with last 22-May-96 2 not very clear, air under resin, split in junction along second line 22-May-96 3 last line clearest, structure and colour under changing polarised light help show lines better 02-Jun-96 1?2? can only see one definite line near edge, lot of disturbance 02-Jun-96 2 slide far too thick, lot of disturbance, appear to be two lines 02-Jun-96 1?2? last line fairly clear, second one dubious, in places looks real, not much growth between the two 02-Jun-96 2 a lot of brown colouration around last line, lines around it but is a dip, same with line 2 29-Jul-96 2? lot of disturbance, last line fairly clear, second one has a dip but not so clear 09-Sep-96 2 very thin slide, clearer under higher magnification especially around junction 09-Sep-96 2 two lines, clearer under low magnification, meet with dips in junction and ligostracum breaks 09-Sep-96 3? very difficult, lot of lines but at lower mag. last two lines stick out, another possible further back 09-Sep-96 2 L and R sides on slide, lines fairly clear on both and match up, both meet dips in junction 01-Oct-96 2? very odd for an October shell, both lines fairly clear but occur with bumps rather than dips? 01-Oct-96 3? a lot of disturbance, first one fairly clear but not totally convinced 01-Oct-96 1?2? only one line, not much change in structure, last line very defined 01-Oct-96 2 confusing, has 2 lines, both more defined than others, line at edge may cause confusion 18-Nov-96 broken during thin sectioning process 18-Nov-96 bad bond 18-Nov-96 2 fairly clear, edge starting to dip, lines defined, disturbance lines also 18-Nov-96 2 both lines fairly clear, edge slightly broken so cannot see whether dipping or not 18-Nov-96 2 both lines clearly defined, big hump in between, no dipping on edge 02-Dec-96 1 1 definite line, very clear definition, no dipping although edge could be mistaken for line forming 02-Dec-96 3? edge is very disturbed, would be very difficult to estimate season from this 02-Dec-96 2 slide too thick, not quite dipping at edge, lines quite defined, disturbance also 02-Dec-96 2 both lines fairly well defined with dips, edge starting to dip but only a little 17-Mar-97 4 all lines thin and defined and associated with dips in junction, also lines in ligostracum April-97 2 lot of holes in structure, growing edge bit destroyed, 2 fairly clear lines with dips and ligo lines April-97 2? 2 lines, one very near edge, 2 not so clear but more likely than other disturbance lines 22-Apr-96

2

112

0.2

1.8

0.2

2.8 2.7

0.3

1.9 1.8

0.2

2.4

0.15

1.5 1.8

0.2 0.5

2.2

0.5

1

0.5

2.8

0.3

2.1

0.9

1.6

1.6

2.6

1.4

1.8 1.4

1.4

2.7

0.6

1.6

0.8

1.9

1.2 0.7

2.1

? ? 1.7

2.8

1.4

2.5

1.6

2.5

1.9 1

2.2 1.4

? 1.5

2

0.1

1.5 2.2 2.2

0.15

1.6

0.2

2.6

APPENDIX 1 T.12.O.9.R

Site R T.1.R.7.R T.1.R.7.R T.1.R.8.R T.1.R.9.L T.1.R.11.L T.1.R.12.L T.1.R.12.L T.2.R.6.L T.2.R.8.L T.2.R.9.L T.2.R.10.R T.3.R.5.L T.3.R.6.L T.3.R.7.L T.3.R.8.R T.4.R.6.R T.4.R.8.L T.4.R.9.R T.4.R.10.L T.5.R.3.L T.6.R.7.R T.6.R.8.R T.6.R.10.L T.6.R.12.L T.6.R.13.R T.7.R.7.L T.7.R.8.L T.7.R.9.R T.7.R.11.L T.7.R.12.R.

April-97

1?2? not good thin section, some shell removed by grinding, lot of lines and brown staining

0.1

broken during thin sectioning broken during thin sectioning 3 line literally just formed on edge, disturbance lines lot thicker, big dips in junction 22-Mar-96 3? annual lines more visible under low mag. lot of other disturbance lines, last line on edge 22-Mar-96 2? line right on edge, other fairly clear although thin section is perhaps too thick 22-Mar-96 broken during thin sectioning 22-Mar-96 bad bond to slide 22-Apr-96 2 last line at edge, quite clear, second clearer under low magnification, some disturbance 22-Apr-96 2? last line on edge, line in ligostracum also, second seen more from colour changes and small dip 22-Apr-96 2 last line near edge, big dip and well defined, other not so clear, break in junction, slide thick 22-Apr-96 3 line just forming on edge, evidence in ligo. 2 others fairly well defined 22-May-96 2 last line clear but also many disturbance lines, other not so clear but dip and clearer further down 22-May-96 2 both lines fairly clear, there are other lines but they are not well defined 22-May-96 2 last line clear, not defined but see at low mag. from colour changes, other not so clear 22-May-96 2 last line clear, definition and dip, disturbance lines, one is more likely and has line in ligo 02-Jun-96 2 lines not particularly clear, definition under high mag. lines in ligo., lot of disturbance also 02-Jun-96 2 probably 2 lines, some definition although slide too thick, seems to be a lot of growth for June 02-Jun-96 3 appear to be 3 lines, again a lot of growth for June, last line well defined, dip and triangle, Feb? 02-Jun-96 1?2? very thin slide, over-ground, line hard to make out, need polarising light changes, broken at edge 29-Jul-96 2 2 lines fairly clear, dips, ligostracum lines clear, especially last line 19-Aug-96 2 both lines clear, join the junction, other disturbance lines do not, patterns in structure and colour 19-Aug-96 2 particularly difficult one, a lot of disturbance and ligo has come away from shell, lines thinner 19-Aug-96 3 3 fairly clear lines, mid-line between last and growing edge quite thick, lines in ligo and dips 19-Aug-96 2 quite difficult, last line has a dip in junction, second seen from changes in colour and structure 19-Aug-96 2 last line quite well defined, second not except at junction, disturbance, line very near edge 09-Sep-96 4 under low mag. all lines fairly clear, matching ligo. lines and dips 09-Sep-96 3 last 2 lines defined, occur with dips and ligo line matches, others in between not continuous 09-Sep-96 2? lot of disturbance lines, annual ones less thick, all have dips and ligo. no help 09-Sep-96 1?2? fairly clear defined line and ligostracum lines, mid-line between this and edge 09-Sep-96 1?2? last line defined, occurs with dip, mid-line between this

? ? 1.3

1.8

1.7

2

22-Mar-96 22-Mar-96 22-Mar-96

113

2.7 ? ? 0.1

2.2

2.4 0.1

2.2

2.1

2.6

0.3

2.3

0.4

2.7

0.4

2.4

0.2

3

1

2.2

2.1

2.9

1.8

2.6 2.3

1.4 1

2.4

1.2

2.6

1.6

2.8

0.7

2

1.3

2.5

0.4

2.4

0.8

1.5 1.8

1

2.2 2.4

1.9

2.5

1.2 1.2

3.2

2.1

2

APPENDIX 1

T.8.R.5.L

01-Oct-96

T.8.R.7.R

01-Oct-96

T.8.R.8.R

01-Oct-96

T.10.R.7.L

02-Dec-96

T.10.R.8.L

02-Dec-96

T.10.R.9.L

02-Dec-96

T.10.R.11.L

02-Dec-96

T.10.R.10.L

02-Dec-96

T.11.R.4.R

17-Mar-97

T.11.R.5.L T.11.R.5.L T.11.R.6.R

17-Mar-97 17-Mar-97 17-Mar-97

T.12.R.7.R

April-97

T.12.R.8.L T.12.R.9.L

April-97 April-97

T.12.R.10.L

April-97

T.12.R.11.L

April-97

and edge on a bump in junction 2 lines but not particularly clear, patterning in structure and colour helpful 2 appear to be 2 lines, also disturbance lines, clearer at junction 1? would probably have to discard this one, possible break but not clear, structure messy near edge 2 probably cause confusion, appears to be line on edge, also triangle 1 not very clear line but seen from structure and colour, triangle but no line at edge 2 2 lines seen from structural changes, triangle and dipping down, some disturbance lines also 1 quite a clear line, meets dip in junction and ligo. line, slide too thick, edge dipping over 2 both lines fairly clear compared to disturbance ones, dips and very small triangle at edge 2? very confusing, rollercoaster topography of junction, lot of disturbance, edge dipping and triangle broken during thin sectioning bad bond to slide 2? both lines unclear, little triangle on edge and some dipping, no evidence of line 3 disturbance lines but 2 more obvious under low mag., can just see a line forming on edge 2 2 definite lines under low mag., no major dips, 1?2? definite line near edge, change in structure possibly indicating another line 2 last line just formed, other defined more by colour and structural changes 3 appears to be 3 lines, one near edge, dip and triangle, third not so clear 2?

1.1

2

1.2

1.9

1.6? 2.1 1.9 1.4

2.5

1.4 1.9

1.9

1.9

3

? ? 1.2

2.5

2

2.2

0.15 0.15

2.5

0.05

2.6

0.05

1.8 1.9

Whitstable Identity

Left W.1.2.L W.1.2.R W.1.9.L W.1.9.R W.1.10.L W.1.10.R W.1.14.L W.1.14.R W.1.15.L

Age Notes

Years

2

lines fairly clear, shell broken so missing older structure, line on edge, compare measurements 2 1 line and 1 forming on edge, some dipping, thicker mid-line in this last band 3?4? possibly 3 lines and 1 forming on edge? opaque so hard to tell here, holes also problem 4 matches with above, 4 lines, some dips, not all lines particularly clear 4? 3 lines and maybe one on edge, opaque at edge, others coincide with dips 4 any line at edge obscured by opaque area, some lines in ligostracum, dips and clear lines 3 not particularly clear, cannot see anything at edge, some dips, undulating junction 3 similar to above, not very clear, some structural patterning, lot of confusing mid-lines 5? under low mag. can see structure and colour changes, most bands have mid-lines, dips 114

0-1

1-2 2-3 3-4 4-5 5-6

0.15

2.4

0.1

3

0.4

1.6 1.6

5

0.4

1.6 3.2 3.4

1.2

1.9 2.3

2.4

2.9

2.4

2.4 2.1

2.3

3.2 2.4

2.1

1.7 2.1 2.1 2.4

3

APPENDIX 1 W.1.15.R

5?6? too thick, line may possibly be forming at edge, mid-lines and structure showed patterning

Right W.1.17.L

3

W.1.17.R

?

W.1.18.L

3

W.1.18.R W.1.19.L W.1.19.R

? 2 2

W.1.20.L

?

W.1.20.R

2

W.1.21.L

3?

W.1.21.R W.1.22.L

3

W.1.22.R

3

W.1.23.L

?

W.1.23.R

4?

W.1.24.L W.1.24.R W.1.25.L

3 3

W.1.25.R

?

W.1.26.L W.1.26.R W.1.27.L

3

W.1.27.R W.1.28.L

3?4?

W.1.28.R W.1.29.L

3

W.1.29.R W.1.30.L W.1.30.R

2?3? 2?3? 3

W.1.31.L

2?

W.1.31.R

3

W.1.32.L

3?4?

W.1.32.R

0.2

may be a line on edge but not clear, structure very complex even 1.9 under higher mag. either overground or very badly cut, would have to discard it, ? cannot identify anything 3 lines, 1 on edge, fairly clear, dips and lines in ligo., bit 1.5 overground really overground structure away, would have to discard ? 2 clear lines, cannot see any at edge, triangle in ligo, mid-lines, 1.8 similar to above, could mistake mid-line for annual if not careful 2 as occurs with a dip bad slide as hand prepared, maybe one line, growing edge dips ? down, new line about to form? bit clearer, dip and triangle at edge, lot of disturbance in last year, 1.8 structural changes used possibly a line at the edge, one line very clear, the other has a 2.1 dip but not clear bad cut, sloping edge, very confusing structure, discard ? 3 annual lines? although appear to a lot of other lines, line at 2 growing edge probably too thick, no line seen at edge, 3 lines but 3 mid-lines could easily 1.8 be mistaken as annuals useless, broken at junction, split, conchiolin line and looks ? overcut as well very different to above, one line at edge, others very clear with 1.6 dips, some mid-lines too difficult, edge sloping off due to over grinding or bad cut, ? useless bit too thick, measurements seem too large, cut? line on edge 3.4 quite clear, dips and structure changes, line at edge but also 0.2 some conchiolin bad slide, calcified area at edge, mixed up structure, colour ? indicates 2 possible breaks conchiolin line near edge, split structure, cannot see much at ? growing edge so would reject it as above but worse, too much splitting due to conchiolin ? overground too much, edge sloping off, lines fairly clear though, 1.7 one at edge discard ? some may have broken off the back, line right on edge, mid-lines 1.2 and annuals very similar too overground and badly made slide, discard ? line just forming at edge, really dipping down, others convincing 2.6 with mid-lines in between too thick, cannot see if line is forming, not so clear as above 2.3 mid-lines and annuals similar, colouring helps a little 1.6 appears to be line on edge, clearer under low mag., mid-lines 1.8 cause confusion problem with slide, lifted as was unfrosted, under low mag. 2 clearer, may be one on edge? dissimilar to above, probably line forming on edge, mid-lines 1.8 confuse interpretation low mag. line on edge, lines not very clear, measurements seem 3.4 quite large discard ?

115

2.3 1.7

3.3

2.7

2.2 1.6

2.4 3

2 2.6 2.4

1.7 2.7

3.5 1.4 2.6

3

2.4

2

3.6 3.4 1.9 2.5 2.2 1.5 1.5 2.6

2

2.6 3.5

APPENDIX 2

Appendix 2 List of the 50 slides chosen by the administrator and used in Blind test 1, and the reordering for runs 2 and 3. Sample C.3.A.12.A T.11.O.5.R S.7.B.6.L W.1.2.L T.8.O.10.R C.7.A.15.L S.10.F.6.L C.8.H.9.R W.1.15.L C.13.J.20.L T.2.W.10.L S.9.F.4.L C.8.E.17.L T.9.O.8.R S.10.H.9.R S.5.E.16.L W.1.2.R T.8.O.11.R T.7.R.7.L C.9.A.9.L S.10.B.11.R C.12.J.14.Rb W.1.15.R T.2.R.9.L S.3.I.19.R T.8.O.8.R C.7.H.11.L S.1.H.7.L T.10.R.11.L C.12.J.11.Ra T.4.W.12.L S.3.D.10.R C.3.J.15.Ra S.9.F.4.R S.12.F.10.R C.3.E.18.R W.1.23.R T.5.R.3.L S.10.L.6.R C.10.H.12.L S.13.C.14.L C.12.J.9.L T.12.R.11.L S.8.F.6.L C.13.E.9.L W.1.23.L T.5.U.6.R S.6.L.5.L C.3.J.15.Rb S.5.C.6.R

Run 1 Run 2 Run 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

4 29 37 14 50 31 19 26 38 16 41 47 17 27 1 21 10 35 8 43 42 3 24 49 30 6 7 45 18 5 40 2 9 39 48 11 15 28 22 25 12 36 20 46 32 23 34 13 33 44

37 50 26 33 22 40 15 9 45 2 28 31 49 5 19 34 11 1 42 3 39 41 8 32 16 10 18 35 7 48 4 46 47 12 6 14 43 13 21 38 24 27 17 25 44 20 36 29 23 30

116

APPENDIX 2

Results of Blind Testing Results of the 3 runs as written at the time and the novice blind test

Blind test 1 Run 1: 9th February 1998 Sample 1 2 3

Age 4 4? 2?

Month May April/May August

Season line formed line formed growth

4 5 6 7 8 9

? 4 3 4 5 8?

April/May Sept July Dec Nov March

line formed late summer summer winter early winter winter

10 11 12 13 14

5 or 6 4 5? 4? 4 or 5

March May Nov Sept/Oct Dec/Jan

spring post line late in year late in year pre line

15 16 17 18

3 4 4 3?

May April Oct?

post line post line autumn

19 20

4 3

Sept Nov

late summer line formed

21 22

2 3?

Nov Feb

early winter pre line

23 24 25

7? or 8 3 2

April May Dec/Jan

post line post line pre line

26

4

Oct

late summer

27

2 prob 3

Nov

late in year

28 29

2 or 3 1

Dec/Jan Nov/Dec

late in winter winter

30 31

4

May?

spring/summer

32 33

4 7??

March March

on line on line

34

Comments probably Chelmsford, site A? line right on edge line right on edge only one line visible, used measurement to give mid summer probably Whitstable, bad sample Chelmsford Southampton, conchiolin Chelmsford, lines are clear breaks, no triangle or dip yet age very hard, bad slide, could be early spring, could be line on edge Chelmsford Truro, lines not clear Southampton, really hard, last band very wide Chelmsford, lines clear breaks probably 5 lines, Southampton? conchiolin lines, not Chelmsford bad slide, on a slant, possibly July but discarding it clear lines but also conchiolin, site? Whitstable, looks same as no. 4, but is easier to read really hard, there is dipping, perhaps would be easier to discard Chelmsford, looks line is just forming on edge until move the polarising light around Southampton, clear annual lines but also conchiolin lines clear lines, could be Chelmsford, mid-lines also v clear, looks like about to form line line just formed, Whitstable, looks like no. 9 Truro, not very clear Tricky, on a slant, probably, Southampton, edge v different, can't see if line is about to form either Truro or Southampton, probably Truro as lines not very clear Chelmsford, really tricky, looks like a line on edge in some lights on a slant, but quite a bit of growth, could be earlier or later too thick, not enough dipping for later, enough growth for winter Chelmsford, discard, far too many lines, definitely site J Truro, v tricky, hard to read, may be a lot earlier, think line near edge is annual line Southampton, just about to form line Chelmsford, Site J again, matches 34, from colour could be March really hard, can't make out lines, discard 117

APPENDIX 2 35 36 37 38 39 40 41 42

3 or 4 4 3 2 3? 4? 2 4

Feb April/May April August

pre line line line summer

Dec March March?

winter line late spring

43

4

May

post line

44

2

Oct

late summer

45

3

March

pre line

46 47 48 49

3 3?? 7?

July July March

post line post line line

50

3?

June/July

post line

Southampton? Quite clear, probably an estuary site Southampton or Chelmsford, quite clear Whitstable, bad slide but can make out lines Truro Southampton, can't tell what’s what, discard Chelmsford Southampton big mid-lines, deceiving, Chelmsford, could well be July, maybe should discard line just formed, Truro or Southampton, not clear lines but lots of conchiolin on a bit of a slant, season probably more accurate than month, tricky Chelmsford, tricky as on a slant, does actually look like line is forming no way can read, definitely discard look at patterning Southampton, probably near Pennington most definitely Chelmsford, Site J again. Is a remake of 33, and reverse of 30 looks like Truro, may be Southampton

Run 2: 27th February 1998 Sample 1

Age 3

Month Oct

Season

2 3 4 5 6

4 3 or 4 4 ? 4

April Feb April/May Feb?? Aug/Sept

line forming

7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

3 4 ? 4 4 3 or 4 ? 2 3 4? 4 2 5 5? ? 4 or 5 ?

Nov Aug March April April March June April April March Oct Jan March April April

autumn late summer line line formed line formed line formed summer line formed line formed forming autumn winter line line formed line formed

23 24 25

6 4

April Dec

spring winter

spring pre-line autumn

Comments not very clear, either Truro or Southampton, cut on skew, possibly should discard dipping down on edge really hard as lines not particularly clear Chelmsford, very clear, probably site A, line just formed Impossible, Chelmsford, Site J, Difficult, on a bit of a skew, mid-line formed but not enough growth or dipping for later starting to dip but not enough growth for later than autumn Site J, matching 5, looks like line has just formed on the edge Whitstable Chelmsford Southampton, conchiolin lines Truro? Whitstable, lines not particularly clear Whitstable line just forming mid-line formed, probably Chelmsford, could be later in year past mid-line, dipping on edge, faint line on edge Southampton, line just formed on edge, dipping Southampton not at all clear, conchiolin lines, Southampton or Truro Too unclear, many lines, looks like one on edge but not sure whether annual line impossible line has formed, Whitstable Site A? Chelmsford

118

APPENDIX 2 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

5 4 4? 3 3or 4 3 3 ? 3 3 4? 2 6or 7 ? 3 or 4 2 3 3 2

46 47 48 49 50

2 4or 5 3 3? 4?

Nov Dec Sept April/May March August March March July

autumn/winter autumn/winter late summer spring spring late summer spring spring summer

line on edge, hard to see as ligostracum junction broken little triangle formed mid-line formed, bit ambiguous, Truro?

Southampton or Truro Chelmsford, mid-line so past July ? line forming Site J, Chelmsford, matches 9 and 5 Truro, mid-line just on edge very difficult, lines bit ambiguous, Truro, discard March spring Difficult, mid lines, very convincing Chelmsford August summer Hard to compare as only one other band, Southampton April spring Whitstable, matches 24 Too tricky, too many similar lines Too tricky, no lines are clear, Truro April/May spring Not very clear, but can see line right on edge Dec winter pre-line, Southampton Nov autumn/winter Chelmsford, triangle just formed May spring Southampton, line just formed probably Dec winter too much on a skew, probably Southampton, could be slightly earlier or later Sept late summer Southampton Oct autumn Southampton, lines a bit unclear but the mid line has just formed Feb/March spring Southampton May spring Truro Oct autumn Southampton or Truro

Run 3: 10th March 1998 Sample

Age

1 2 3 4 5 6 7 8 9 10

? 3 3 2 3 2 2 3 4 3

11 12 13 14 15 16 17 18 19 20

Month

September late summer April line formed December pre line July summer December pre line Feb/March pre line Oct/Nov autumn April line October autumn August post mid-line

3 April 3 or 4 September 3 August 4 April 5? December 3 3 3 3

Season

April May September December

line autumn summer spring winter spring post line autumn winter

Comments Truro? Chelmsford Chelmsford Truro Southampton/Truro Southampton Southampton? Hard as only one band to compare to Whitstable Chelmsford Really hard, probably Truro, not clear and season may well be later but only a little growth Whitstable Southampton Southampton? Chelmsford Southampton, could be later, March as looks like line is forming, not sure Southampton Southampton no triangle yet Southampton, really hard, edge very ambiguous No way! 119

APPENDIX 2 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

3 3 ? 2 or 3 2 2 6 3 or 4 3 2 3? 3 3 3 2 3? 4 4 2 3 or 4 4 4 4 3 or 4 4? 4 ? ? 4 or 5 4?

January October March/April March September August March April June May Sept/Oct May April March/April December July May December November August February September April March April March March February September March

spring autumn spring spring summer summer spring spring summer summer autumn spring spring spring winter summer summer winter winter summer spring autumn spring spring spring pre-line spring spring autumn spring

Truro Southampton? very difficult, Truro? Site J, Chelmsford Southampton Southampton Southampton, difficult as little previous growth to compare with Chelmsford Truro Southampton Southampton very difficult, but last band has mid-line Truro Whitstable Southampton Southampton Truro site A, Chelmsford Chelmsford Southampton Tricky, last band so small, Chelmsford Chelmsford Chelmsford Tricky, Truro Southampton? Whitstable, matches 8? Southampton, tricky Site J, Chelmsford Site J, Chelmsford Chelmsford Truro

Blind test 2: novice Number 2-20 slides from run 3, test 1 Sample Age 2 3

4 1

4 5 6 7 8 9 10 11 12

5 5 3 1 4

13 14

2 2

2 3

Month

Comments

March/April Big dipping and possibly new line formed, not sure about previous annual line though July can only see one clear annual line, difficult, from structure etc. would GUESS July but is guess! Really can't tell Jan/Feb annual line quite dodgy, one near edge clearer, good dipping on edge, almost new line Dec/Jan very similar to #5. maybe dipping nope! line formed 3 definite annual line, possibly 2 others, not sure about edge, possibly line just formed Sept/Nov edge v difficult to see, from structure = Sept/Nov July 3 annual lines, but quite difficult to see April/May very difficult, can't see annual lines, think may have just formed new one Aug/Sept lots of disturbance, not really sure about all annual lines but pretty certain about one near edge Aug/Sept from structure would say Aug/Sept but slight dipping so not sure if about to form new line Dec? starting to dip on the edge 120

APPENDIX 2 15 16 17 18 19 20

2 2 2?

June? April? Dec? June/July

loads of disturbance, can't distinguish annual line, major conchiolin line 2 annual lines, no dipping just formed new line? Can't see beyond 2, many disturbance lines total mess, can't really see much but edge dipping? 1 quite near edge No way.

121

APPENDIX 3

Appendix 3 Appendix 3 presents the interpretations of the thin sections of the archaeological samples from Norsminde, Visborg, Dyngby, Lystrup, Havnø and Eskelund made when analysing the thin sections under the polarising light microscope in February 1998. The hinge measurements taken at the cataloguing stage have been included. These measurements were used in chapter 8 when they were plotted against the ages of the shells in order to compare size/age ratios between sites and through time. The notes are observations made when analysing the slides. A rough indicator of the stage in growth in relation to line formation is given as well as the estimated month of death. The annual lines identified were numbered back through the oyster so the newest line nearest the edge was 1, the next 2 and so on. The year 0-1 represents the measurement between the last line and the growing edge, the year 1-2 would represent the previous years growth etc. If a line has just formed on the edge or is forming the year 0-1 would be the measurement of the last band, that is between the growing line and the previous line. All measurements are in millimetres. The records marked in bold indicate that the photograph is included in chapter 8 and therefore the notes can be cross-referenced with these.

Norsminde Identity

Hinge Age

Layer 1 N.1.5.L

7.46

4

N.1.6.R N.1.7.R

5.81 3.89

2 2

N.1.8.L

6.45

2

N.1.9.L N.1.11.R

6.37 5.84

3 2

N.1.12.R N.1.13.L

4.73 4.88

Layer 2 N.2.1.R

7.9

3

N.2.2.L

4.73

2

N.2.3.L N.2.4.L N.2.5.L N.2.6.R N.2.7.L

6.25 3.06 4.45 4.15 6.32

2

2 2

Notes

Stage

dip and years growth, possibly line right on edge line just formed line near edge, not particularly clear sample slide not very good, appears to be line on edge, is dipping looks like line has formed on edge not very clear but there is a line near edge, structure a bit messy discarded during thin sectioning discarded during thin sectioning, cut off badly

clear specimen, little broken at top of edge but line clearly formed dipping and line right on edge, seen under high mag. very clear, mid-line just formed discarded during thin sectioning discarded during thin sectioning end of yearly cycle, line about to form 2 fairly clear lines, edge slightly broken but clear line just formed 122

Result

Years 0-1

1-2 2-3 3-4 4-5

pre-line

April

1.2

1.5

3

line post line

May May/June

2.2 0.2

2.2

line

April/May

1.6

2.2

line post line

May May/June

1.7 0.2

1.7 2.8

May/June

0.2

2.6 2.4

April

2.4

July/Aug

0.5

3

April May

2.2 0.1

3.8

? ?

post line line post line ? ? pre-line post line

APPENDIX 3 N.2.9.L N.2.10.L N.2.11.L

6 3.69 5.81

2 2 2

N.2.12.L

5.8

Layer 3 N.3.1.L N.3.2.L

7.66 8.44

3 3

N.3.3.L

7.33

4

N.3.5.L

4.8

1

N.3.7.R N.3.8.R N.3.9.L

3.95 4.42 4.63

2

N.3.10.L N.3.11.L

4.73 4.94

1 1

N.3.12.R

7

4

Layer 4 N.4.1.R

6.86

2

N.4.3.L N.4.4.L

5.57 5.61

N.4.5.L

6.93

N.4.5.R N.4.6.L

6.93 4.99

N.4.7.L N.4.8.R

8.4 8.09

N.4.9.L

5.1

N.4.10.L

5.73

very clear, mid-line between 2 lines, line right on edge 2 fairly clear, line looked to be on edge 2 line near edge but no mid-line, orange line adjacent to line 2 2 burnt, structure harder to see, mid-line may have formed 2 as above 1 looks like mid-line has formed, only one line visible 4 bit burnt, dipping and years growth 3? difficult, grey structure, looks like line is near the edge 2? very hard, cracks along it, edge bit broken, dark, structure unclear discarded, slide broken

Layer 5 N.5.1.L

5.19

3

N.5.2.L N.5.3.L

5.97 7.48

N.5.4.L

4.08

N.5.5.L

5.03

N.5.6.R N.5.7.L

7.1 5.3

2

N.5.8.L

7.52

2

2

1

lines very clear, quite a lot of growth fairly clear, line near edge badly made slide but last line quite clear discarded during thin sectioning

clear structure line easier to observe high mag., surrounded by darker material edge bit broken in places, further down line 0.2mms from edge one line is clear, back of the shell is broken discarded during thin sectioning sample peeled off slide clear structure, orange line on edge side of last line very clear, mid-line may be forming very clear, looks like line on edge but probably a mid-line appears to be 3 lines, 1 big disturbance line, lot of disturbance

unclear structure, not clear, years growth and looks pre-line discarded during thin sectioning ligostracum survived, edge dips, line forming iron oxide stains, no definite lines observed some staining, structure unclear but can see line near edge discarded during thin sectioning edge dipping down, line just forming on edge edge dipping down, line just forming on edge

123

post line post line post line

June May July/Aug

0.4 0.1 0.5

3.7 1.8 2.8

post line post line

May May

0.15 0.1

2.2 1.7 1.9 2.5

post line

May

0.2

0.9 1.7

post line

June

0.4

? ? post line

June

0.4

post line post line

July/Aug July/Aug

0.5 0.5

post line

May/June

0.3

line

April

2.7

line post line

April July

3 0.6

2

pre dip

August

1.4

3.4

pre dip pre dip

August July/Aug

1.5 0.5

3.1

March May

1.7 0.1

1.8 1.6

pre-dip

August?

0.7

1.7

pre-line

Feb/March

0.9

1

April

1

1.3

?

dip post line

? line ?

?

post line

May

0.2

? line

April

2.6

line

April

2.7

2.3

2.6 2.5

2 2

1

APPENDIX 3 N.5.9.L N.5.10.R

5.8 8.08

2 3

very clear, line just forming on edge edge dipping down and years growth, orange line next to last line 3? lot of staining, bad slanted cut so not measured, line near to edge

line pre-line

April March

N.5.11.R

5.48

Layer 6 N.6.3.R N.6.4.L

8.06 7.63

post line

May

4

post line ?

June

0.4

1

N.6.5.R N.6.6.L

5.45 9.9

3

? pre-line

March

2

2.5

N.6.7.L N.6.8.L N.6.9.R

5.71 7.19 6.86

5 3 3

line post line line

March/April May April

1 0.3 1.8

1.4 1.5 1.7 2 2.8 1.6

N.6.11.L

9.32

4

April

1.5?

2.1

N.6.12.R

4.26

N.6.13.L

7.93

5

pre-line

March

0.4

0.9 1.5 1.5

Layer 7 N.7.3.R

7.68

4

post line

May

0.05

1.3 2.5

N.7.5.L

7.82

4

pre-line

March

0.9

1.5 2.8

N.7.6.L

9.31

5

line

April

1.6

1.1 1.7 2.9

N.7.7.L

7.15

3

line

April

1.1

3.3

N.7.8.L N.7.9.L

8.07 7.29

3 4

line pre-line

April March

2 0.9

2.4 1.6 1.7

N.7.11.L

6.58

2

pre-line

March/April

2.6

N.7.12.L

9.69

4

pre-line

March

1.9

N.7.13.L N.7.14.L

6.14 8.54

2 4

? April

1

Layer 8 N.8.3.L

7.55

3

pre-line

March?

1.9

2.9

N.8.4.L

10.85

5

pre-dip

August

0.35

1.1 1.1 1.4 2.4

N.8.5.L

8.2

3

pre-line

Feb/March

2

2.6

N.8.6.L

8.41

4

line

April

2

1.8 1.7

N.8.7.R

6.05

3

line

April

2

2.4

N.8.9.R N.8.10.R

8.45 5.92

4 2

line line

April April

1.9 2.7

2.4

N.8.11.L

6.98

clear structure, discarded during thin sectioning, problem with resin discarded during thin sectioning edge dipping down and line about to form looks like line is forming on edge fairly clear structure, line near edge fairly clear, bit stained, line right on edge edge sloping right over, line forming on edge discarded during thin sectioning, sample peeled off slide very difficult, last band very thin, lot of disturbance but prob. March

growth bent over, still fairly clear, line just formed may be cut bit on a slant, line forming on edge bands differing widths, line definitely forming on edge looks like line has formed on edge, slanted cut, orange line dipping, line just formed mid-line in middle of band, structure looks like line about to form years growth and some dipping, line about to form pattern of structure very clear, line about to form on edge useless as edge is too broken cut on slant, line forming on edge

stained and edge bit rough, probably line about to form clear structure and line, about 5 months growth very difficult, stained and disturbed structure, at high mag. line seen to be forming on edge last band disturbed, lot of line, annual ones clear, line on edge clear structure, dipping, line on edge clear, some breaks, under high mag. line on edge discarded during thin sectioning, 124

line

1.9 1.9

1.3 1.4

3

?

? line

?

3.1

2

3

2.7 2.8

3

APPENDIX 3

N.8.12.R N.8.13.L

7.12 6.61

N.8.14.L

9.53

N.8.15.L

7.96

N.8.17.L

6.37

N.8.22.L

5.83

N.8.23.L

7.23

N.8.24.L

6.95

N.8.25.L

7.52

N.8.26.L

6.53

Layer 9 N.9.1.R

7.01

N.9.3.R

5.4

N.9.4.L N.9.5.R

4.63 7.87

N.9.6.L

6.12

N.9.8.L

9.18

N.9.9.R N.9.10.L

6.42 8.95

N.9.11.R

7.62

N.9.12.R

7.09

N.9.13.R

5.94

N.9.14.R N.9.15.L

6.06 7.04

N.9.17.L

5.97

N.9.18.L

6.73

N.9.19.R

7.17

N.9.20.L N.9.22.L

10.29 6.23

Layer 10 N.10.2.L N.10.3.L

7.24 9.48

problem with resin cut badly, edge bit broken, useless disturbance in last couple of bands, under high mag. line on edge 3 staining on edge, hard to see line, has a years growth and dipping 2 under high magnification line seen on edge 3? under high magnification line seen on edge 3 quite a lot of disturbance, last band thick, line forming on edge 3 edge a bit stained, dip and years growth 2 under high magnification line seen on edge 1? lot of disturbance, looks like a conchiolin line, line formed on edge 3 disturbance in last band, under high mag. line seen on edge 3 5

2

years growth, looks like line is about to form 1 under high magnification line seen on edge 1 line just formed on edge 3 disturbed, dipping and years growth, about to form line 2? disturbed but structure looks like line is about to form 3 fairly clear structure, line definitely formed on edge badly made slide 4 very clear, dipping, looks like line about to form 6 very clear, quite lot of disturbance in last bands, years 5-6 2mms ? most ground out in T.S., bit slanted, line forming on edge 3 cut on a slant, dipping, looks like line forming on edge cut on a slant, no lines visible 3 fairly clear structure, dipping, line about to form ? structure not clear, disturbed, dipping, change of colour on edge 4 line definitely forming on edge, 2 orange lines 4 line on edge seen under high magnification problem with resin 3 edge area broken and disturbed, difficult to interpret

2 line right on edge 5? not clear near edge, and a bit broken

125

? line

? April

0.8

0.9 1.8 1.7

Feb/March

2.2

3.7

line

April

3.1

line

April

2

line

April

2.7

2.2

March/April

3.3

2.2

line

April

2.8

line

March/April

4.3?

line

April

1.4

March/April

2.4

April

1.9

line pre-line

April March/April

2

pre-line

March/April

2.3

line

April

1.4

2.6

pre-line

? March

1.2

1.9 2.1

post line

June

0.1

0.7 0.7 0.7

pre-line

March/April

1.5

1.8

April

0.8

2.6

? pre-line

? March

1.8

3.7

pre-line

March?

2?

line

April

1.5

1.5 1.8

line

April

1.6

1.9 3.2

April

3

pre-line

pre-line

pre-line line

line

? ?

line ?

2.6

3.5

1.1

APPENDIX 3 N.10.5.L

12.78

6

N.10.6.R

8.96

4

N.10.8.L

11.24

4

N.10.9.L

6.97

3

N.10.10.L N.10.12.L

7.1 9.32

4 3

N.10.13.R

7.29

5

N.10.14.L

9.2

4

N.10.15.R

11.16

3

N.10.16.L N.10.17.L N.10.24.L N.10.25.L

6.7 6.7 6.68 9.27

4 3 5

dipping and years growth, line probably about to form on edge fairly clear structure, line formed right on edge slanted cut, edge very dark, too hard to interpret under high mag. line forming on edge, measurements bit odd line right on edge lot of disturbance in last band, looks like line near edge slightly broken near edge but line near edge very clear structure, line right on edge, faint mid-lines dipping, line almost on edge, cut on a slant, orange line fairly clear, line just by the edge very unclear structure, too dense line forming right on edge line forming on edge, 2 orange lines

pre-line

March

1.2

1.1 1.5 2.1 2.6

April

1.8

2.4 3.2

pre-line

March/April

0.8

2.4

line post line

April May

1.5 0.2

1 2

post line

May/June

line ?

line

3.5 2.4

0.8 0.9 1.5 1.9

April

1.2

1.5 2.8

post line

April/May

0.6

1.2

4

post line ? line line

May

0.1

1.2

2

April April

1.7 1

2.5 1 1.2 2.9

3.4

Visborg Identity

Hinge Age

Notes

Stage

Result

Years 0-1

Sample 1 V.1.3.R

9.73

3

V.1.4.R

7.1

3

V.1.6.R

10.79

4

V.1.7.R

13.76

5

V.1.8.L V.1.9.R

7.27 7.07

3

V.1.10.L

8.52

4

V.1.13.R

7.58

3

V.1.14.R

8.03

Sample 2 V.2.2.R 10.71

4

V.2.3.L

5.65

3

V.2.4.R V.2.6.L

7.64 6.73

3 3

V.2.8.L

7.26

2

burnt, no dipping, from colour and structure suggests autumn line appears to be forming on edge very difficult, may be a line on edge but dark patches obscuring disturbed, dark patches at edge, line 0.1mms from edge high mag. eroded on edges, orange line edge broken but appears to be line near edge looks like line is forming on edge dark at edge but line 0.2mms from edge badly made slide and cut at a slant

very clear, edge dipping down, line right on edge edge a bit eroded, years growth cut on a slant, years growth edge bit eroded, line forming on edge edge bit broken, some growth

1-2 2-3 3-4 4-5 5-6 6-7

pre dip

Aug/Sept

1

2

line

March/Apri l

1

1

line post line ? post line

0.8 0.1

1

May

? 0.7

0.7

1.1

2.2 1.4

0.2

1.2 2.5

March/Apri l post line June ?

pre line pre line line

1.2 1.6

?

March/Apri l March

Jan/Feb March/Apri l post line June/July 126

1.1 2.2 2.2

May

line

line

3.2

1.7 1.1 1.4 1.5 ?

2.4 3.7 1

1.4

1.6 2.2 3 1.7

2

APPENDIX 3

V.2.9.R

7.29

3

V.2.10.L V.2.11.R

13.26 5.81

8 3

V.2.12.L V.2.13.L

3.06 7.59

3

Sample 3 V.3.1.R 12.76

3

since last line dipping, patterning and years growth indicate about to form line very difficult as so old edge slopes off, slightly later in year? line 0.6mms from edge broken shell colour and structure indicate line about to form

V.3.2.R

16.91

V.3.3.R

5.02

V.3.4.R

8.73

edge bit stained, line soon to form on edge 11 end of year, line about to form, yrs 7-10; 1.2, 2.3, 3.2 2 from structure and colour line is about to form 5 line just formed on the edge

V.3.6.R

12.32

6

V.3.7.L

8.05

4

V.3.8.L

8.7

2

V.3.9.L V.3.10.L V.3.11.L

11.15 8.4 5.37

6 5

Sample 4 V.4.2.R

7.09

3

V.4.3.R

10.08

4

V.4.5.R

10.36

4

V.4.6.R

7.47

4

V.4.7.L

10.51

2

V.2.8.L V.4.9.L V.4.11.R

8.45 9.56 5.51

2 2

Random V.R.1.R

10.46

4

V.R.2.L

6.69

3

V.R.4.R

10.95

3

V.R.6.L

10.93

5

very clear, line just formed, orange line along second line cut on a slant, dipping a bit, probably about to form a line very difficult, cut on a slant, thin band but looks like line on edge dipping, line definitely on edge line 0.2mms from edge ground away

little dipping, from colour and structure looks like line about to form very clear, line just formed on the edge edge dips right down, very clear, line just forming edge broken, later in year, line about to form? edge bit broken, some staining, unclear line just formed problem in impregnation stage line on edge, seen best at ligostracum junction

last band bit broken, colour and structure suggest later in year line appears to be forming on edge line about to form

pre line

Feb/March

0.7

1.1 1.6

? pre dip

Sept

0.5 0.6

1 1.1 1.2 1.2 3.5

? 1.9

2.4

pre line

March/Apri l

pre line

Jan/Feb

3.1

3.6

pre line

Feb/March

1.3

0.6 0.8

pre line

Feb/March

2.7

line

1

line

March/Apri l March/Apri l Feb/March

pre line

1

1

0.7 1.1 1.4

1.2 1.4 2.9

2.1

1.2 1.1 1.1 3.6

0.9

1.6

2

line

March/Apri l

1.2

line post line

March May/June

0.9 0.2 ?

0.7 1.1 1.7 2.6 0.7 0.8 1.4 2

pre line

March

1.6

2.1

line

April/May

1.5

1.5 2.3

line

April/May

1.4

1.4

pre line

?

? line ? line

post line line pre line

very clear, line just formed on line edge 127

3

1.3 2.4

1.6

2.3

0.1 ? 2.7

2.9

October?

0.9

2.2 2.1

March/Apri l March/Apri l April

2.2

1.7

2.7

3.8

0.9

1

April/May March/Apri l

3

1.7 1.6

1.5 3.1

APPENDIX 3 V.R.7.R

7.69

6

V.R.8.L

5.97

4

V.R.9.L

8.66

4

V.R.10.L

8.27

3

V.R.12.L

10.75

4

V.R.13.L

9.78

5

disturbance in last years, line appears to be forming on edge some breakage on edge, dipping, just about to form a line some dipping, large band, line about to form structure and years growth indicate line about to form edge dipping, looks like line is forming, burnt but fairly clear dipping, clear structure indicates line about to form

line

April

0.6

1

1

1.9 2.5

pre line

March/Apri l

1.2

pre line

March

2.5

2

pre line

March

2.2

2

pre line

March

1.2

1.7 2.9

pre line

March

1.2

0.9 1.3 2.8

1.5 1.8 2.9

Dyngby Identity

Hinge Age

Notes

Stage

Month

Years 0-1

Sample 1 D.1.7.R

7.52

D.1.9.L D.1.10.L D.1.14.L D.1.15.R

5.75 5.81 5.82 6.8

D.1.16.R D.1.17.L D.1.18.L

7.68 5.3 5.59

D.1.19.L

4.55

3? edge dips a little, years growth, line about to form 2 years growth but no evidence for line 2 years growth but no evidence for line 2 years growth but no evidence for line 2 some staining, structure would suggest line is about to form 2 line definitely forming on edge 2 line definitely forming on edge 2 under high magnification looks as though line forming on edge 2 edge broken

Sample 2 D.2.5.R D.2.6.L

7.91 8.22

3 3

D.2.7.R

7.91

3

D.2.8.L

6.41

4

D.2.9.R D.2.10.L

8.37 5.77

3 3

D.2.14.L

7.11

Sample 3 D.3.1.R D.3.4.R D.3.6.R D.3.16.R D.3.17.L D.3.20.R

5.11 7.26 4.28 3.37 3.51 6.6

D.3.24.R

3.67

1 1

2 2

line 0.15mms from edge fairly clear, quite a bit of growth since last line from structure pattern line looks about to form some staining, under high mag. looks as though line is forming line 0.5mms from edge, mid-line just formed bit stained, edge dipping, looks as though line about to form discarded during thin sectioning process

some staining, line 0.5mms from edge edge is broken too small and not clear too small and not clear line about 0.1mms from edge under high magnification line can be seen on edge discarded as cut from slide badly

128

pre line

March

2.4

pre line pre line pre line pre line

Jan/Feb March Jan/Feb Feb/March

3.2 2.8 3.2 2.6

March/April March/April March/April

2.7 3 1.7

line line line

1-2 2-3 3-4

3

post line post line

May June/July

0.15 0.9

3.4 3.3 2.6 2.7

pre line

March

1.5

2.2

line

March

1.1

2

July/Aug March

0.5 1

1.8 2.5 2

June/July

0.5

1.6

May April

3.1 0.1 2.2

1.2

mid-line pre line ?

post line

post line line ?

2.2

APPENDIX 3 Random D.R.6.L

6.17

D.R.7.L D.R.8.L D.R.9.L D.R.11.L D.R.13.L

3.91 5.97 4.20 4.78 4.62

D.R.17.R

7.97

D.R.20.R D.R.28.L D.R.36.L

5.24 6.21 8.44

2

1

2 1 3

clear specimen, edge slightly stained, years growth, line forming edge broken difficult, lot of disturbance lines edge broken edge broken edge slightly broken, line about 0.2mms from edge very broken and no obvious patterning in structure cut on slant looks as though line is forming on edge difficult, looks like about 6 months growth, perhaps a little later?

line

March/April

?

3.2

1

post line

May/June

2.8

0.2

?

1?

line pre dip

April Sept?

1.2 3 1.1

Result

Years

2.9 1.6

Eskelund Identity Hinge Age

E.1.L E.2.R E.3.L E.6.R E.9.L

6.75 5.87 11.36 10.97 9.05

3 2 3 3 3

E.10.R E.11.L E.12.L E.15.L E.16.R E.17.R E.18.R

5.57 7.42 13.04 6.58 6.19 6.52 9.67

2 5 3 3 2 3

E.19.R

9.25

E.21.L

6.89

E.22.L E.23.L E.24.R E.25.R

7 5.03 8.09 8.83

2 2

E.26.L E.27.L

8.86 5.6

3 2

3

Notes

Stage

looks as though line is forming possibly line on edge stained a bit, line formed on edge some growth since last line some staining, looks as though mid-line has formed discarded during thin sectioning process structure too dense at edge difficult, edge a bit eroded fairly clear, years growth, about to form a line edge dipping down, line forming dipping on edge, line forming on edge some dipping on edge, looks like a line is forming some disturbance, too hard to interpret, red lines badly made broken slide, edge still intact, line forming line about 0.2mms from the edge line about 0.2mms from the edge discarded during thin sectioning process edge broken a little but there is a line 0.2mms from edge edge dips a little, looks like a line about to form line about 0.3mms from edge

line line line post line mid-line

Notes

Stage

pre line line line line

9.18 9.02

too broken too broken 129

March March March/April June/July July/august

2 1.9 2.1 0.6 1

2.6

March March March/April March

1 1.3 1.6 1.6 2.2 1.7

?

1.6

line post line post line ? post line

2.4 3.2 2.4 2.4 2.2 2.9 2.4

Result

Years

1.9 2.7 3.2 1.6 2.4 3.4 2.4 0.8 2.2 2.4

March

2

May May/June

0.2 0.2

2.3 1.3

May

0.2

2.1 2.2

2 0.3

2.7

pre line March post line May/June

0-1 L.2.L L.5.R

1-2 2-3 3-4

?

Lystrup Identity Hinge Age

0-1

APPENDIX 3 L.6.L L.7.L L.8.L L.10.L L.11.L L.12.L L.14.L L.15.L L.16.R L.17.L L.18.L

14.94 12.15 5.31 8.19 10.7 7.69 7.65 5.8 6.57 8.49 13.79

too broken too broken 3? line near edge possibly a line near edge too broken too broken 2? may be a line right on edge too broken too broken 5 possibly a line on the edge too broken

post line post line

June/July June/July

line

April/May

line

April/May

Havnø Identity Hinge Age

H.1.L H.3.L

9.33 16.07

H.4.L

15.61

H.5.L

10.29

H.6.L

5.21

H.7.L

9.69

H.8.L

5.94

H.9.L H.10.L

8.6 9.51

H.11.L

5.98

H.12.R

10.14

H.13.L H.14.L H.15.L H.16.L H.17.R

8.67 8.57 6.85 9.13 13.79

H.18.L

13.64

Notes

Stage

4 7

very clear, line about to form pre line line appears to be forming on the line edge 11 about to form line, last years 1.5, pre line 3 4 very difficult, cut on a slant, line pre line possibly about to form 3 difficult, looks as though line pre line about to form 3 edge slightly darker, possibly a pre line line about to form 3 dipping, and line can be seen on line edge too broken and confused 5 looks like a line has formed on line the edge discarded during thin sectioning ? process 7 very clear, dipping, line forming line on edge 3 no dipping but full years growth pre line 2 broken at edge 3 line just formed on edge line 3 edges too eroded 6 edge a little eroded, line about to pre line form 5 line just forming on edge line

130

Result

Years 0-1

1-2 2-3 3-4 4-5 5-6 6-7

March March

2.1 1.4

2.1 3.2 1.2 1.8

March

1

March?

0.4

1.4 1.5

March?

1.3

1.7

March?

1.5

2.5

March/April

1.2

2.1

March/April

1.4

2.2 1.6

March/April

1.3

1.8 1.8 1.1

Feb/March

2.4

2.4

April

2.2

2.4

March?

1.5

2

March/April

1.5

2

2.2 2.4

1.3 0.9 0.7 1.1 1.2

2

1

3

1.3 1.2 1.4 2.8

1.7 1.9 2.4

1

BIBLIOGRAPHY

Bibliography Albrethsen, S.E. and E. Brinch Petersen 1977. Excavation of a Mesolithic cemetery at Vedbæk, Denmark. Acta Archaeologica 47, 1-28

Andersen, S. H. 2000. Fisker og bonde ved Visborg. In Hvass, S. og Det arkæologiske Nævn (eds.) Vor skjulte kulturarv, 14 – 15

Andersen, S.H. 1974. Ringkloster: en jysk inlandsboplads med Ertebøllekultur. (English summary). Kuml 1973-74, 11-108

Andersen, S. H. 2001. Danske køkkenmøddinger anno 2000. In Jensen, O. L., S. A. Sørensen & K. M. Hansen (eds.) Danmarks jægerstenalder - status og perspektiver, 21- 42

Andersen, S.H. 1976. Et østjysk fjordsystems bebyggelse i stenalderen. Norsminde Fjord undersøgelsen. In H. Thrane (ed.) Bebyggelsesarkæologi. Beretning fra et symposium d. 7.-8. Nov. 1975 afholdt af Odense Universitet. Skrifter fra Institut for Historie og Samfundsvidenskab, Odense Universitet 17, 18-62

Andersen, S.H. and E. Johansen 1987. Ertebølle Revisited. Journal of Danish Archaeology 5, 1986, 31-61 Andresen, J.M., Byrd, B.F., Elsom, M.D., McGuire, R.H., Mendoza, R.G., Staski, E. and J.P. White 1981. The Deer hunters: Star Carr reconsidered. World Archaeology 13 (1), 31-46

Andersen, S.H. 1980. Ertebølle Art. New finds of Patterned Ertebølle artefacts from East Jutland. Kuml 1980, 4957

Bailey, G.N. 1975. The Role of Shell Middens in Prehistoric Economies. Unpublished Ph.D thesis, University of Cambridge

Andersen, S.H. 1985. Tybrind Vig. A preliminary report on a submerged Ertebølle settlement on the West coast of Fyn. Journal of Danish Archaeology 4, 52-69

Bailey, G.N. 1978. Shell Middens as Indicators of Postglacial Economies. In P. Mellars (ed.) The Early Postglacial Settlement of Northern Europe: An Ecological Perspective. London: Duckworth, 37-64

Andersen, S.H. 1991. Norsminde. A “kokkenmødding” with Late Mesolithic and Early Neolithic Occupation. Journal of Danish Archaeology 8, 1989, 13-40

Bailey, G.N., Deith, M.R. and N.J. Shackleton 1983. Oxygen Isotope Analysis and Seasonality Determination: Limits and potential of a new technique. American Antiquity 48, 390-398

Andersen, S.H. 1993a. Mesolithic Coastal Settlement. In S. Hvaas and B. Storgaard (eds.) Digging into the Past, 25 Years of Archaeology in Denmark. Copenhagen: The Royal Society of Northern Antiquaries, 65-68

Becker, C.J. 1973. Problemer omkring overgangen fra fangstkulturer til bondekulturer i Sydskandinavien. Bonde - Veidemann. Bofast - ikke Bofast i Nordisk Forhistoire. In P. Simonsen and G. Stamsø Munch (eds.) Tromsø Museums Skrifter XIV, Tromsø, Oslo, Bergen: Universtitetsforlaget, 6-21

Andersen, S.H. 1993b. Bjørnsholm. A Stratified Køkkenmødding on the Central Limfjord, North Jutland. Journal of Danish Archaeology 10, 1991, 59-96 Andersen, S. H. 1995. Coastal Adaption and Marine Exploitation in Late Mesolithic Denmark- with specific emphasis on the Limfjord region. In A. Fischer (ed.) Man and Sea in the Mesolithic. Coastal settlement above and below present sea level. Oxford: Oxbow Books, 41-66

Bennike, P. 1993. The People. In S. Hvass and B. Storgaard (eds.) Digging into the Past: 25 years of Danish Archaeology. Aarhus: Universitetsforlag, 34-39 Blumenschine, R.J., Marean, C.W. and S.D. Capaldo 1996. Blind tests of inter-analyst correspondence and accuracy in the identification of cut marks, percussion marks and carnivore tooth marks on bone surfaces. Journal of Archaeological Science 23, 493507

Andersen, S.H. 1996. Ertebøllebåde fra Lystrup. Ertebølle canoes from Lystrup. Kuml 1993-1994, 7-38 Andersen, S.H. 1998. Ringkloster. Ertebølle trappers and wild boar hunters in eastern Jutland. A survey. Journal of Danish Archaeology 12, 1994-1995, 1350 131

BIBLIOGRAPHY Bratlund, B. 1993. The Bone Remains of Mammals and Birds from the Bjørnsholm Shell-Mound. Journal of Danish Archaeology 10, 1991, 97-104

Coutts, P.J.F. 1970. Bivalve-growth Patterning as a Method for Seasonal Dating in Archaeology. Nature 226, 874

Burke, A.M. 1993. Observation of incremental growth structures in dental cementum using the scanning electron microscope. Archaeozoologia V/2, 41-54

Coutts, P.J.F. 1974. Growth characteristics of the Bivalve Chione stutchburyi. New Zealand Journal of Marine and Freshwater Research 8, 333-339

Carter, J.G. 1980. Environmental and Biological Controls of Bivalve Shell Mineralogy and Microstructure. In D.C. Rhoads and R.A. Lutz (eds.) Skeletal Growth of Aquatic Organisms. Biological Records of Environmental Change. London: Plenum Press, 69113

Coutts, P.J.F. 1975. The Seasonal Perspective of MarineOrientated Prehistoric Hunter-Gatherers. In G.D. Rosenberg and S.K. Runcorn (eds.) Growth Rhythms and the History of the Earth’s Rotation. London: Wiley, 243-252 Coutts, P. and C. Higham 1971. The Seasonal Factor in Prehistoric New Zealand. World Archaeology 2, 266277

Carter, R.J. 1998. Reassessment of Seasonality at the Early Mesolithic Site of Star Carr, Yorkshire Based on Radiographs of Mandibular Tooth Development in Red Deer (Cervus elaphus). Journal of Archaeological Science 25 (9), 851-856

Coutts, P.J.F. and K.L. Jones 1974. A Proposed Method for Deriving Seasonal data from the Echinoid, Evechinus chloroticus (Val.) in Archaeological Deposits. American Antiquity 39 (1), 98-102

Caulfield, S. 1978. Star Carr - an Alternative View. Irish Archaeological Research Forum 5, 15-22

Custer, J.F., and K.R. Doms 1990. Analysis of Microgrowth Patterns of the American Oyster (Crassostrea virginica) in the Middle Atlantic Region of Eastern North America: Archaeological Application, Journal of Archaeological Science 17, 151-160

Claassen, C. 1991. Normative thinking and shell bearing sites in archaeology. In M.B. Schiffer (ed.) Archaeology Method and Theory 3, London: Academic Press, 249-298 Claassen, C. 1993. Problems and Choices in Shell Seasonality Studies and their Impact on Results. Archaeozoologia V/2, 55-76

Darling, F. 1937. A Herd of Red Deer. Oxford: Oxford University Press

Claassen, C. 1998. Shells. University Press

Cambridge

Davis, S.J.M. 1987. The Archaeology of Animals. London: B.T. Batsford Ltd

Clark, J.G.D. 1954. Excavations at Star Carr: An Early Mesolithic Site at Seamer Carr near Scarborough, Yorkshire. Cambridge: Cambridge University Press

Deith, M.R. 1983. Molluscan Calendars: The Use of Growth-line Analysis to Establish Seasonality of Shellfish Collection at the Mesolithic Site of Morton, Fife. Journal of Archaeological Science 10, 423-440

Cambridge:

Clark, J.G.D. 1972. Star Carr: A Case Study in Bioarchaeology. Addison-Wesley Module in Anthropology 10

Deith, M.R. 1985. Seasonality from Shells: An Evaluation of Two Techniques for Seasonal Dating of Marine Molluscs. In N.R.J. Fieller, D.D. Gilbertson and N.G.A. Ralph (eds) Palaeobiological Investigations: Research, Design, Methods and Data Analysis. Oxford: BAR (IS) S266, 119-130

Clark, J.G.D. 1975. The Earlier Stone Age Settlement of Scandinavia. Cambridge: Cambridge University Press Clark II, G.R. 1980. Appendix 1. Study of molluscan shell structure and growth lines using thin sections. In D.C. Rhoads and R.A. Lutz (eds.) Skeletal growth of aquatic organisms. Biological records of environmental change. London: Plenum Press, 603606

Deith, M.R. 1986. Subsistence Strategies at a Mesolithic Camp Site: Evidence from Stable Isotope Analyses of Shells. Journal of Archaeological Science 13, 1678 Deith, M.R. 1988. A Molluscan Perspective on the Role of Foraging in Neolithic Farming Economies. In G. Bailey and J. Parkington (eds.) The Archaeology of Prehistoric Coastlines. Cambridge: Cambridge University Press, 116-124

Collins, M.J. and Riley, M., 2000. The Interpretation of Aspartic Acid Racemization Data. In G.A. Goodfriend, M.J. Collins, M.L. Fogel, S.A. Macko and J.F. Wehmiller (Eds.) Perspectives in Amino Acid and Protein Geochemistry. New York: Oxford University Press, 120-144

Deith, M.R. 1989. Shellfish Gathering and Site Function: a Case Study from the Neolithic Apulia. Archaeozoologia III/1,2, 163-176 132

BIBLIOGRAPHY

Enghoff, I.B. 1991. Fishing from the Stone Age Settlement of Norsminde. Journal of Danish Archaeology 8, 1989, 41-50

Hodder, I. 1990. Domestication of Europe. Structure and Contingency in Neolithic Societies. Oxford: Blackwell

Enghoff, I.B. 1993. Mesolithic Eel-Fishing at Bjørnsholm, Denmark, Spiced with Exotic Species. Journal of Danish Archaeology 10, 1991, 105-118

Horwitz, J. 1973. Early Agriculture in Southern Scandinavia: A New Model. Norwegian Archaeological Review 6 (2), 53-58

Enghoff, I.B. 1994. Fishing in Denmark during the Ertebølle period. International Journal of Osteoarchaeology 4, 65-96

House, M.R. and G.E. Farrow, 1968. Daily Growth Banding in the shell of the Cockle, Cardium edule. Nature 219, 1384-1386

Farrow, G.E. 1971. Periodicity Structures in the Bivalve Shell: Experiments to Establish Growth Controls in Cerastoderma edule from the Thames Estuary. Paleontology 14 (4), 571-588

Ingebrigsten, O. 1924. Hjortens Utbredelse i Norge. Bergen: Naturvidenskabelige rekke no. 6 Iversen, J. 1941. Landnam i Danmarks stenalder. Danmarks Geologiske Undersølgse, II Rk., 66, 7-68

Farrow, G.E. 1972. Periodicity Structures from the Bivalve Shell: Analysis of Stunting in Cerastoderma edule from the Bury Inlet (South Wales). Paleontology 15, (1), 61-72

Jacobi, R.M. 1978. Northern England in the Eight Millenium bc: an Essay. In P.A. Mellars (ed) The Early Postglacial settlement of Northern Europe: an ecological perspective, London: Duckworth, 295-332

Fischer, A. 1982. Trade in Danubian Shaft-Hole Axes and the Introduction of Neolithic Economy in Denmark. Journal of Danish Archaeology 1, 7-12

Jarman, M.R., Bailey, G.N., and H.N. Jarman 1982. Early European Agriculture. Its Foundation and Development. Cambridge: Cambridge University Press

Fitzhugh, B. 1995. Clams and the Kachemak: Seasonal Shellfish use on Kodiak Island, Alaska (1200-800 B.P.). Research in Economic Anthropology 16, 129176

Jennbert, K. 1985. Neolithisation - a Scanian perspective. Journal of Danish Archaeology 4, 196-7

Fraser, F.C. and J.E. King 1954. Faunal remains. In J.G.D. Clark (ed.) Excavations at Star Carr. Cambridge: Cambridge University Press, 70-95

Jochim, M. 1981. Strategies for Survival. Cultural Behaviour in an Ecological Context. London: Academic Press

Froom, G. 1979. A Study of Molluscs and Otoliths from the Prehistoric Coastal Midden of Norsminde, Denmark. Unpublished M.Phil. Dissertation, University of Cambridge

Jochim, M. 1991. Archaeology as Long Term Ethnography. American Anthropologist 93, 308-321 Johansen, K.L. in press. Settlement and Land Use at the Mesolithic-Neolithic Transition in Southern Scandinavia. Journal of Danish Archaeology 13, 1996-97

Gordon, B.C. 1993. Archaeological Tooth and Bone Seasonal Increments: the Need for Standardized Terms and Techniques. Archaeozoologia V/2, 9-16

Kennet, D.J. and B. Voorhies 1996. Oxygen isotope analysis of Archaeological shells to Detect Seasonal use of Wetlands in the Southern Pacific Coast of Mexico. Journal of Archaeological Science 23, 689704

Gordon, J. and M.R. Carriker 1978. Growth Lines in a Bivalve Mollusk: Subdaily Patterns and Dissolution of the Shell. Science 202, 519-521 Grigson, C. 1981. Fauna. In I.G. Simmons and M.J. Tooley (eds.) The Environment in British Prehistory. London: Duckworth, 110-124

Kennish, M.J., Lutz R.A. and D.C. Rhoads 1980. Shell Microgrowth Analysis. Mercenaria mercenaria as a Type Example for Research in Population Dynamics. In D.C. Rhoads and R.A. Lutz, (eds) Skeletal Growth of Aquatic Organisms. Biological Records of Environmental Change. London: Plenum Press, 255294

Grønnow, B. 1987. Meiendorf and Stellmoor Revisited. An Analysis of Late Palaeolithic Reindeer Exploitation. Acta Archaeologia 56, 1985, 131-166 Heinzel, H., Fitter, R and J. Parslow 1974 (3rd ed.) The birds of Britain and Europe. London: Collins

Kent, B., 1988. Making Dead Oysters Talk. Techniques for analysing Oysters from Archaeological Sites. Maryland Historical Trust, Historic St. Marys City, Jefferson Patterson Park and Museum.

Hodder, I. 1982. The Present Past: An Introduction to Anthropology for Archaeologists. London: Batsford 133

BIBLIOGRAPHY Koike, H. 1980. Seasonal Dating by Growth-Line Counting of the Clam, Meretrix lusoria, Toward a Reconstruction of Prehistoric Shell-Collecting Activities in Japan. Tokyo: University of Tokyo Press, Bulletin No.18

Mellars, P.A. 1976. Settlement Patterns and Industrial Variability in the British Mesolithic. In G. de G. Sieveking, I.H. Longworth and K.E. Wilson. Problems in Economic and Social Archaeology. London: Duckworth, 375-399

Korringa, P. 1951. The Shell of Ostrea edulis as a Habitat. Archives Neérlandises de Zoologie 5, 1-249

Mellars, P.A. and M.R. Wilkinson 1980. Fish Otoliths as Indicators of Seasonality in Prehistoric Shell Middens: the Evidence from Oronsay (Inner Hebrides). Proceedings of the Prehistoric Society 46, 19-44

Korringa, P. 1957. Lunar periodicity. Geological Society of America 67 (1), 917-934 Krause, W. 1937. Die eiszeitlichen Knochenfunde von Meiendorf. Das altsteinzeitliche Rentierjäger Meiendorf. A. Rust. Neumünster, Karl Wachholz Verlag, 48 - 61

Midgely, M.S. 1992. TRB Culture. The First Farmers of the North European Plain. Edinburgh: Edinburgh University Press Milner, N. 1998. Seasonality Information from the Incremental Growth of the European Oyster for Ertebølle sites in Denmark. Unpublished Ph.D. thesis, University of Cambridge

Larsson, L. 1984. The Skateholm Project. A late Mesolithic settlement and cemetery complex at a southern Swedish bay. Meddelanden från Lunds Universitets Historiska Museum, 1983-4, 5-38

Milner, N. 2002. Oysters, Cockles and Kitchenmiddens: Changing Consumption Practices at the Mesolithic/Neolithic Transition. In P.T. Miracle and N. Milner (eds.) Consuming Patterns and Patterns of Consumption. Cambridge: McDonald Institute

Larsson, M. 1987. Neolithization in Scania – a Funnel Beaker perspective. Journal of Danish Archaeology 5, 1986, 244-247 Lawrence, D.R. 1988. Oysters as Geoarchaeologic Objects. Geoarchaeology 3 (4), 267-274

Milner, N. in press. Pitfalls and Problems in Analysing and Interpreting the Seasonality of Faunal Remains. In N. Milner and D.Q.Fuller (eds.) Animal Bones in Archaeology: Archaeological Review from Cambridge 18:1

Legge A.J. and Rowley-Conwy P.A. 1988. Star Carr Revisited: A Re-analysis of the Large Mammals. London: Centre for Extra-Mural Studies, Birbeck College

Monks, G.G. 1981. Seasonality studies. In M.B. Schiffer (ed.) Advances in Archaeological Method and Theory 4. New York: Academic Press, 177-240

Lentacker, A. and W. Van Neer 1996. Bird Remains from Two Sites on the Red Sea Coast and some Observations on Medullary Bone. International Journal of Osteoarchaeology 6, 488-496

Møhl, U. 1979. Aggersund-bopladsen zoologisk belyst. Svanejagt som årsag til bosættelse? (Zoological analysis of the Aggersund settlement: a specialpurpose camp for hunting swans?). Kuml 1978, 5776

Lutz, R.A. and D.C. Rhoads 1977. Anaerobiosis and a Theory of Growth Line Formation. Science 198, 1222-1227 Lutz, R.A. and D.C. Rhoads 1980. Growth Patterns within the Molluscan Shell: An Overview. In D.C. Rhoads and R.A. Lutz (eds), Skeletal Growth of Aquatic Organisms. Biological Records of Environmental Change. London: Plenum Press, 203-254

Nield, Robert, 1995. The English, the French and the Oyster. London: Quiller Press Nielson, P.O. 1987. The Beginning of the Neolithic Assimilation or Complex Change? Journal of Danish Archaeology 5, 240-3

Madsen, A.P., Müller, S., Neergaard, C., Petersen C.G.J., Rostrup, E., Steenstrup, K.J.V, and H. Winge 1900. Affaldsdynger fra Stenalderen i Danmark. Undersøgte for Nationalmuseet. København

Noe-Nygaard, N. 1975. Two Shoulder Blades with Healed Lesions from Star Carr. Proceedings of the Prehistoric Society 41, 10-16 Orton, J.H. 1928. On Rhythmic Periods in Shell Growth in Ostrea edulis with a Note on Fattening. Journal of the Marine Biological Association of the UK 15, 365-427

Madsen, T. 1987. Where did all the Hunters go? An Assessment of an Epoch-Making Episode in Danish Prehistory. Journal of Danish Archaeology 5, 1986, 229-239

Orton, J.H., 1937. Oyster Biology and Oyster-Culture. London: Arnold

Meehan, B. 1982. Shellbed to Shell Midden. Canberra: Australian Institute of Aboriginal Studies. 134

BIBLIOGRAPHY Paludan-Müller, C. 1978. High Atlantic Food Gathering in North-Western Zealand, Ecological Conditions and Spatial Representation. In K. Kristiansen and C. Paludan-Müller (eds.) New Directions in Scandinavian Archaeology. Copenhagen: National Museum of Denmark, 120-157

Growth Rate of the European flat oyster, Ostrea edulis, in British waters Determined from Acetate Peels of Umbo Growth Lines. ICES (International Council for the Exploration of the Sea) Journal of Marine Science 50, 493-500 Rocek, T.R. 1998. Pithouses and Pueblos on Two Continents: Interpretations of Sedentism and Mobility in the Southwestern United States and Southwest Asia. In T.R.Rocek and O. Bar-Yosef (eds.) Seasonality and sedentism. Archaeological Perspectives from Old and New World Sites. Harvard University: Peabody museum of archaeology and ethnology

Petersen, E. B. 1973. A Survey of the Late Palaeolithic and Mesolithic of Denmark. In S.K. Kozlowski (ed.) The Mesolithic of Europe. Warsaw: University Press, 325-331 Pitts, M. 1979. Hides and antlers: a New Look at the Gatherer-Hunter Site at Star Carr, North Yorkshire, England. World Archaeology 11 (1), 32-42

Rowley-Conwy, P. 1981. Mesolithic Danish Bacon: Permanent and Temporary sites in the Danish Mesolithic. In A. Sheridan and G.Bailey (eds.) Economic Archaeology, BAR (IS) S96, 51-55

Price, T.D. 1985. Affluent Foragers of Mesolithic Southern Scandinavia. In T.D. Price and J.A. Brown (eds.) Prehistoric Hunter-Gatherers. The Emergence of Cultural Complexity. London: Academic Press Inc., 341-363

Rowley-Conwy, P. 1983. Sedentary Hunters: The Ertebølle Example. in G. Bailey (ed.) Hunter-Gatherer Economy in Prehistory. A European Perspective. Cambridge: Cambridge University Press, 111-129

Price, T.D. 1996. The First Farmers of Southern Scandinavia. In D.R. Harris (ed.) The Origins and Spread of Agriculture and Pastoralism in Eurasia. London: UCL Press, 346-362

Rowley-Conwy, P. 1984. The Laziness of the Shortdistance Hunter: The Origins of Agriculture in Western Denmark. Journal of Anthropological Archaeology 3, 300-324

Price, T.D. 2000. The Introduction of Farming in Northern Europe. In T.D. Price (ed.) Europe’s First Farmers. Cambridge: Cambridge University Press, 260-300

Rowley-Conwy, P. 1985. The Origin of Agriculture in Denmark: A Review of some Theories. Journal of Danish Archaeology 4, 188-195

Quitmyer, I.R. Jones, D.S. and W.S. Arnold 1997. The Sclerochronology of Hard Clams, Mercenaria spp., from the South-Eastern U.S.A.: A Method of Elucidating the Zooarchaeological Records of Seasonal Resource Procurement and Seasonality in Prehistoric Shell Middens. Journal of Archaeological Science 24, 825-840

Rowley-Conwy, P. 1998. Meat, Furs and Skins: Mesolithic Animal Bones from Ringkloster, a Seasonal Hunting Camp in Jutland. Journal of Danish Archaeology 12, 1994-1995, 87-95

Rhoads, D.C. and R.A. Lutz 1980. Skeletal Records of Environmental Change. In D.C. Rhoads and R.A. Lutz (eds.) Skeletal Growth of Aquatic Organisms. Biological Records of Environmental Change. London: Plenum Press, 1-19

Rust, A. 1937. Das altsteinzeitliche Rentierjägerlager Meiendorf. Neumünster

Richards, M.P. and R.E.M. Hedges 1999a. Stable Isotope Evidence for Similarities in the types of Marine Foods used by Late Mesolithic Humans at Sites along the Atlantic Coast of Europe. Journal of Archaeological Science 26, 717-722

Schulting, R.J. and M.P. Richards 2000. The use of Stable Isotopes in Studies of Subsistence and Seasonality in the British Mesolithic. In R. Young (ed.) Mesolithic Lifeways. Current research from Britain and Ireland. Leicester: Leicester Archaeology Monographs 7, 55-65

Rust, A. 1943. Die alt- und mittelsteinzeitlichen Funde von Stellmoor. Neumünster

Richards, M.P. and R.E.M. Hedges 1999b. A Neolithic Revolution? New Evidence of Diet in the British Neolithic. Antiquity 73, 891-897

Shackleton, N.J., 1973. Oxygen Isotope Analysis as a Means of Determining Season of Occupation of Prehistoric Midden Sites. Archaeometry 15, 133-141

Richardson, C.A., Crisp, D.J. and N.W. Runham, 1979. Tidally Deposited Growth Bands in the Shell of the Common Cockle, Cerastoderma edule (L.). Malacologia 18, 277-290

Spikins, P. 1999. Mesolithic Northern England. Environment, Population and Settlement. Oxford: BAR Publishing, British Archaeological Reports British Series 283,

Richardson, C.A., Collis, S.A., Ekaratne, K., Dare, P. and D. Key, 1993. The Age Determination and 135

BIBLIOGRAPHY Stein, J.K. 1992. Deciphering a shell midden. New York: Academic Press Inc. Tauber, H. 1972. Radiocarbon Chronology of the Danish Mesolithic and Neolithic. Antiquity Vol. XLVI, 106110 Tauber, H. 1981. 13C Evidence for Dietary Habits of Prehistoric Man in Denmark. Nature 292, 332-333 Thomas, J. 1988. Neolithic Explanation Revisited: The Mesolithic-Neolithic Transition in Britain and Scandinavia. Proceedings of the Prehistoric Society 54, 59-66 Troels-Smith, J. 1953. Ertebølletidens Fangstfolk og Bønder. Nationalmuseets Arbejdsmark 1960, 95-119 Troels-Smith, J. 1982. Vegetationshistoriske vidnesbyrd om skovrydning, planteavl og husdryhold i Europa, specielt Skandinavien. Introduksjonen av jordbruk i Norden. In Thorlief Sjøvold (ed.) Foredrag holdt ved fellesnordisk symposium i Oslo april 1089. Oslo, Bergen, Tromsø: Universitetsforlaget, 39-62 Trolle-Lassen, T. 1987. Human Exploitation of Fur Animals in Mesolithic Denmark - a case study. Archaeozoologia I2, 85-102 Vang Petersen, P. 1984. Chronological and Regional Variation in the Late Mesolithic of Eastern Denmark. Journal of Danish Archaeology 3, 7-18 Walne, P.R. 1958. Growth of oysters (Ostrea edulis L.) Journal of marine biology association UK 37, 591602 Walne, P.R. 1974. Culture of Bivalve Molluscs, 50 years of experience at Conwy. The Buckland Foundation Wye, K.R. 1991. The Illustrated Encyclopaedia of Shells. London: Headline Book Publishing PLC Yonge, C.M. 1960. Oysters. London: Collins, The New Naturalist Series Zvelebil, M. and P. Rowley-Conwy 1984. Transition to Farming in Northern Europe: A Hunter-Gatherer Perspective. Norwegian Archaeological Review 17 (2), 104-127

136

Index

A

D

acetate peels · 30- 34, 45, 96 etching · 30-31 hydrochloric acid · 31-32 sodium hypochlorite acid · 31 ageing · 65, 67, 93 Aggersund · 2, 4 Anbarra · 97 Andersen, S.H. · 3, 4, 7, 69-75, 88, 97 annual lines · 18, 26-28, 31-32, 35, 36, 40, 44-47, 49, 54, 57, 58, 62, 64, 65, 67, 88, 96 Albrethsen, S.E. et al. · 4 Andresen, J.M. et al. · 3

Darling, F. · 2 Davis, S.J.M. · 2 Deith, M.R. · 2-3, 8, 10, 16-17, 30-32, 88 Differential staining · 30 disturbance lines · 35 conchiolin line · 40 mid-lines · 40-41, 52, 65 others · 40 Dyngby · 32, 69, 74-75, 77, 80-81, 90-94, 96-97

B Bailey, G.N. · 2- 4, 6 barnacles · 22, 23, 24, 26, 27 Becker, C.J. · 5 Bennike, P. · 5 Bjørnsholm · 4, 6-8, 98 Blind testing · 61-67 Blumenschine, R.J. et al · 61 Bratlund, B.· 2, 6-8 Burke, A.M. · 32

C Carrick Roads · 18, 25-26, 28 Carter, J.G. · 10 Carter, R.J. · 3 Caulfield, S. · 3 Chelmsford · 18-22, 24, 26-28, 36, 38, 40, 42, 44, 54-55, 57, 62, 65-66, 75, 88, 93 Claassen, C. · 3, 12, 16-18, 46-47, 96, 98 Clark, J.G.D. · 2-5, Clark II, G.R. · 29-31 cockles · 2, 3, 10, 16, 30, 31, 70, 71, 72, 74, 98 Cardium edule · 16 Cerastoderma edule · 16 Chione stutchburyi · 16 Collins, M. · 97 Coutts, P.J.F. · 10, 16, 30-31 Crassostrea sp. · 10-11, 30-31, 45 Custer, J.F. and Doms, K.R. · 10, 29-31, 45

E Ecological analogy · 16 Enghoff, I.B. · 6, 71 Ertebølle · 1-6, 8, 72, 75, 79, 88, 95, 97 Eskelund · 69, 75, 77, 80, 82-83, 91-93, 96 external stress factors for oysters · 13 boring predators · 37 Chrysallida obtusa · 13 Cliona celata · 13 Crepidula fornicata · 13 Drills · 13 Elminius modestus · 14 Odostomia eulimoides · 13 Polydora sp · 13 rough tingle · 13 starfish (Asterias rubens) · 13 sting winkle (Ocenebria (Murex) erinacea) · 13

F Falmouth and Truro Port Health Authority · 22 Farrow, G.E. · 16 feasting · 97 Fischer , A. · 4-5 Fitzhugh, B. · 10, 30 Flynderhage · 70 Fraser, F.C. and King, J.E. · 2 Froom, G. · 70, 72 fur bearing animals · 7

G

M

Gordon, B.C. · 3 Gordon, J. and Carriker, M.R. · 10 Grigson, C. · 3 Grønnow, B. · 2 Gulala · 97

Madsen, A.P et al. · 69, 75 Madsen, T. · 5 MAFF · 18 Maldon District Council · 22 Matai · 97 Meehan, B. · 97 Meiendorf · 2 Mellars, P.A. · 2-3 Menai Strait · 36, 45 Mercenaria spp · 30-31 Mesolithic · 1-3, 5-7, 16-17, 30, 64, 69-72, 75-76, 87-88, 90, 92- 93, 96-98 Mesolithic 2000 conference · 6 Midgely, M.S. · 88 Milner, N. · 16, 23, 97 modern control sample · 2, 15, 17, 19, 28, 46, 75, 88, 93 Monks, G.G. · 1-2 Morton · 16-17, 30 Mytilus edulis · 3 Møhl, U. · 2

H Havnø · 69, 75, 77, 85, 91-93, 96 Heinzel, H. et al. · 7 Hodder, I. · 5, 15 Horwitz, J. · 5 House, M.R. and Farrow, G.E. · 16 human over-exploitation · 98

I incremental growth analysis · 9 Ingebrigsten, O. · 2 isotopic studies · 98 Iversen, J. · 88

N

Jacobi, R.M. · 3 Jarman, M.R. · 16 Jennbert, K. · 5 Jochim , M.· 97 Johansen, K.L. · 4

National Museum of Denmark · 69 New Forest District Council · 22- 23 Nield, R. · 13 Nielson, P.O. · 4 Noe-Nygaard, N. · 2 Norslund · 70 Norsminde · 3- 4, 32, 69-72, 74-77, 86-88, 90, 92-93, 96-98 novice tester · 61-62, 66-68, 96

K

O

Kennet, D.J. and Voorhies, B. · 2 Kennish, M.J. et al. · 30 Kent, B.· 10, 13, 29-31, 45-46 kitchenmidden committee · 75 kitchenmiddens · see shell middens Koike, H. · 31 Korringa, P. · 11,13 Krause, W. · 2 køkkenmøddinger · see shell middens

Oronsay · 2 Orton, J.H. · 13, 18 otoliths · 2, 7-8, 70-71 oxygen isotope analysis · 2, 29-30, 88 oyster external stress factors · 13 filter feeding · 12 hibernation · 12 larvae · 10-11, 14, 22, 93 reproduction · 11 salinity · 23 spawning · 2, 8, 10-11, 13-14, 36, 40, 49, 93

J

L Larsson, L. · 4 Larsson, M. · 5 Lawrence, D.R. · 10 Legge, A.J. and Rowley-Conwy, P. · 2-3 Lentacker, A. and Van Neer, W. · 7 Limfjord · 4, 16 Litorina sea regression · 6 Littorina littorea · 3, 32 Lutz, R.A. and Rhoads, D.C. · 9-10, 30 Lystrup · 69, 75, 77, 80, 91-93, 96

P palimpsests · 97 Paludan-Müller, C. · 5 Petersen, E.B. · 5 Pitts, M. · 2-3 polarising light microscope · 34, 35, 61 Price, T.D. · 1, 4-6

138

Q

T

Quitmeyer, I.R. et al. · 30-31

Tauber, H. · 5, 98 thin sectioning · 31 bonding to a slide · 34 cover slip · 31-32 diamond paste · 32-33 diamond-impregnated saw · 31 grit papers · 32-34 impregnation · 27, 32-34 Loctite · 34 polishing · 30-31, 33-34 preparing the oysters · 32 preparing the sections · 33 resin · 30-34, 80 sectioning the valves · 32 vacuuming · 33 Thomas, J. · 5 transition to agriculture · 1, 5-6, 8, 95, 97-98 Troels-Smith, J. · 5 Trolle-Lassen, T. · 7 Truro · 18-22, 24-28, 36, 39-40, 44, 46-47, 62, 64-66, 88 Tybrind Vig · 4, 7

R relative growth index · 46-47 Rhoads, D.C. and Lutz, R.A. · 9-10, 30 Richards, M.P. · 98 Richardson, C.A. et al · 10-11, 16, 20, 27, 29, 31, 33, 35-36, 45, 65 Ringkloster · 97 River Blackwater · 18, 24, 36 River Croach · 24-25 River Helford · 25-26, 28, 47 River Roach · 24, 28 Rocek, T.R. · 97 Rowley-Conwy, P. · 1-7, 16, 72, 88, 97-98 Rust, A. · 2

S salinity · 5-6, 10, 13, 16, 18, 22-28, 30, 32, 75, 88, 93, 96, 98 scanning electron microscopy (SEM) · 30 Schulting, R.J. · 98 sea squirts · 11, 23, 26 seasonal transhumance · 2 seasonality · 1-3, 6-8, 10, 16-18, 28-30, 35, 46-47, 49, 6162, 64-67, 69, 71-72, 77, 79-80, 88, 90, 93, 95-98 seaweed · 23-24, 26-27 Shackleton, N.J. · 30 shaft-hole axes · 4 shell middens · 1, 3-4, 8, 30, 95-98 shell structure aragonite · 10, 12, 77 calcite · 13 calcium carbonate · 10, 12, 30, 77 conchiolin · 12-14, 30, 40-41, 77, 80 ligostracum · 12, 30, 36, 38-40, 46, 49, 54-55, 67, 80 nacreous shell · 12-13, 21-22, 24, 26, 40 periostracum · 12 prismatic shell · 12-13, 21, 36 Skateholm · 4 social complexity · 1, 4 Solent · 18, 23, 36, 45 Søren H Andersen · 69, 74-75 Southampton · 18-24, 27-28, 36, 40-41, 43, 45, 50-53, 56, 58-59, 62, 65-66, 88-89 Southampton Water. · 18 spawning · 11, 22 Spikins, P. · 97 sponge · 13, 22-23, 26 Star Carr · 2-3 Stein, J.K. · 97 sub-sampling · 27

V Vang Petersen, P. · 4 Vale of Pickering · 2 Vedbaek · 4 Visborg · 69, 72-75, 77, 84, 90-94, 96, 97 Vænge Sø · 4

W Walne, P.R. · 10-12 Whitstable · 13, 18, 20-22, 26-28, 36-37, 40, 44, 46, 62, 6466 Whitstable Harbour Office · 27 Wye, K.R. · 10

Y Yonge, C.M. · 10-13

Z Zvelebil, M. · 5

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