Review: Gathering Time: Dating the Early Neolithic Enclosures of southern Britain and IrelandDocument Transcript
Review: Gathering Time: Dating the Early Neolithic Enclosures of southern Britain and Ireland Originally posted online on 3 January 2012 at rmchapple.blogspot.com (http://rmchapple.blogspot.co.uk/2012/01/review-gathering-time-dating-early.html)Alasdair Whittle, Frances Healy, & Alex Bayliss. Oxbow books, Oxford, 2011. 2 Volumes,xxxviii+992pp. ISBN 978-1-84217-425-8. £45 (via Oxbow) or £50.07 (via Amazon).For anyone with an interest in Irish and British prehistory and, specifically how thechronologies are assembled through radiocarbon dating, the publication of GatheringTime: Dating the Early Neolithic Enclosures of southern Britain and Ireland has beenlong anticipated and much, much desired. It is hard to overstate the importance of thisbook and how it has already rewritten our understanding of Neolithic enclosures, but italso stands as a template for other intensive studies to follow and emulate. The centralimportance of this study is not simply that it uses a lot of new radiocarbon dates forvarious sites, but it is how this data is treated and processed on such a large scale that isalready leading to new and exciting insights into prehistory. As many readers of thisblog, both professional archaeologists and enthusiasts, will be aware, the advance ofabsolute chronologies in archaeology has, in large part, been due to the developmentof radiocarbon dating. Prior to the seminal work carried out by Willard Libby and histeam (James Arnold and Ernie Anderson), archaeological sites and were only datablethrough relative chronological means, such as seriation etc. In 1960 Libby, Arnold andAnderson won the Nobel Prize in chemistry for their work on radiocarbon dating. Thebasis of the method was that the measurement of the amount of the radioactive isotopecarbon 14 (14C) surviving in a sample could be utilised to determine when, say, a piece ofwood had been cut or grain harvested. These early dates relied on the assumption thatthe amount of 14C in the atmosphere had remained constant throughout history and, asthe discipline was in its infancy, the associated standard deviations were also quite
large. Over the years parallel advances in calibration of dates against tree ring curves,more sophisticated methods and machinery, along with increased care and refinementin the selection of materials and samples has led to better results. Today radiocarbondeterminations have better accuracy and precision than ever before. Nonetheless, evenwith careful sample selection and the use of high-quality AMS dating, there is still thepossibility that, when calibrated, the date will range over several decades to centuries.Since the 1990s a number of researchers have explored and developed a statisticalsystem known as Bayesian modelling. The approach derives from the ideas of ThomasBayes, an 18th century Presbyterian minister and mathematician. Simply put, thismethod allows the calculation of how the degree of belief in a given proposition changesdue to additional evidence. In archaeological terms, the application of Bayesianmodelling allows the refinement of radiocarbon dates through the addition of contextualinformation. Such information may include multiple dates for individual deposits,stratigraphic relationships, or even closely datable artefacts such as coins or pottery. Totake an example from my own experience: at Gransha, Co Londonderry, I excavated asmall pit group. A radiocarbon date from charcoal recovered from one of the featuresindicated that it had been deposited in the Early Neolithic period (4930±70 BP), but thedate range was some 405 calibrated years (3943-3538 cal BC). As part ofthe INSTAR Cultivating Societies project at QUB additional radiocarbon dates werecommissioned and then modelled by Rick Schulting and Paula Reimer (Chapple 2008,Appendix 7). The end result was that the potential lifespan of the site was reduced from405 years to 0-50 years – a vast improvement on the earlier result from a singleradiocarbon date. [Introductions to Bayesian modelling may be found here and here].What Gathering Time set out to do was exactly like the example above, but on anenormous scale. Not only was the aim to produce robust chronologies for individualsites, but to then place them in wider chronologies and within their geographic andtypological settings. The book presents 871 radiocarbon dates from nearly40 causewayed enclosures. To assess how causewayed enclosures functioned as part ofthe wider Neolithic landscape and society models were also prepared for a range ofmonument types, including long cairns and long barrows. This brings the total analysedradiocarbon dates to a startling 2350. As such it is the largest Bayesian modellingproject ever undertaken. The central findings of the project are that the main period ofcausewayed enclosure construction lasted from the late 38 th century cal BC to the mid-to-late 36th century cal BC. Although a number of sites had an active life of severalcenturies, many were used for relatively shorter periods – some for only a matter ofdecades. When this data is incorporated into wider models, encompassing the entiretyof the evidence, it is shown that the causewayed enclosures only appeared threecenturies after the first Neolithic practices were established in southern Britain. Theprocess of ‘Neolithisation’ is shown to have begun in south-eastern England and spreadregionally over two centuries.Chapter 1, ‘Gathering time: causewayed enclosure and the early Neolithic of southernBritain and of Ireland’ (Whittle, Healy, & Bayliss) addresses questions of time andchronological resolution, along with a presentation of causewayed enclosures and thehistory of their research. Chapter 2, ‘Towards generational timescales: the quantitativeinterpretation of archaeological chronologies’ (Bayliss, van der Plicht, Bronk Ramsey,
McCormac, Healy, & Whittle) provides an introduction to Bayesian modelling and theproject methodology. In particular, it examines the necessary prerequisites forsuccessful implementation of the Bayesian approach – from prior knowledge aboutsample data (taphonomy, association, stratigraphy etc.) to the tacit statisticalassumptions involved in this form of model building.For the purposes of this project, southern Britain has been divided into what the authorsdescribe as ‘pragmatically defined regions’. Chapters 3-11, each deal with the enclosuresof a southern British region and place them in the context of contemporary Neolithicactivity. In each of these chapters models are presented, along with a review of thebroader implications of the new chronologies. In Chapter 3, ‘The north Wiltshire Downs’(Whittle, Bayliss, & Healy) Windmill Hill, Knap Hill, and Rybury are examined. Chapter4, ‘South Wessex’ (Healy, Bayliss, Whittle, Allen, Mercer, Rawlings, Sharples, &Thomas) looks at Hambledon Hill, Whitesheet Hill, Maiden Castle, and Robin Hood’sBall. Chapter 5, ‘Sussex’ (Healy, Bayliss, & Whittle) presents Whitehawk Camp, OffhamHill, Combe Hill, The Trundle, Bury Hill, Court Hill, Barkhale, and Halnaker Hill.Chapter 6, ‘Eastern England’ (Healy, Bayliss, Whittle, Prior, French, Allen, Evans,Edmonds, Meadows, & Hey) is divided into five sub regions: The Chilterns (MaidenBower); The Great Ouse catchment (Great Wilbraham, & Haddenham); The Nene Valley(Briar Hill); The Lower Welland Valley (Etton, Etton Woodgate, & Northborough); andEast of the Fens. Chapter 7, ‘The Greater Thames estuary’ (Bayliss, Allen, Healy,Whittle, Germany, Griffiths, Hamilton, Higham, Meadows, Shand, Stevens, & Wysocki)presents Lodge Farm, St. Osyth, Orsett, The Essex side of the Thames estuary,Kingsborough 1 and 2, Chalk Hill, The Kent side of the Thames estuary, and The ThamesEstuary and Beyond. Chapter 8, ‘The Thames Valley’ (Healy, Whittle, Bayliss, Hey,Robertson-Mackay, Allen, & Ford) presents Yeoveney Lodge Farm, Staines, Eton Wick,Gatehampton Farm, Goring, and Abingdon. Chapter 9, ‘The Cotswolds’ (Dixon, Whittle,Bayliss, Hey, & Darvill) examines Crickley Hill and Peak Camp. Chapter 10, ‘The south-west peninsula’ (Whittle, Bayliss, Healy, Mercer, Jones, & Todd) presents examinationsof Membury, Hembury, Raddon Hill, Helman Tor, and Carn Brea. Chapter 11 (in volume2), ‘The Marches, south Wales and the Isle of Man’ (Bayliss, Whittle, Healy, Ray,Dorling, Lewis, Darvill, Wainwright, & Wysocki) looks at the sites of Hill Croft Field,Beach Court Farm, Ewenny, Banc Du, and Billown. Chapter 12 ‘Ireland’ (Cooney,Bayliss, Healy, Whittle, Danaher, Cagney, Mallory, Smith, Kador, & O’Sullivan) deals inthe same way as each of the above regions, but with the island of Ireland as a whole. Theexamination of dates from the Donegore Hill and Magheraboy causewayed enclosures,along with a host of associated determinations, allows the authors to argue that theNeolithic in Ireland began around 3800 cal BC. The general conclusion of thesechapters is that there is no precedent for the majority of the elements that define theEarly Neolithic in the preceding Mesolithic. These innovations include thedomestication of animals, cereal cultivation, rectangular timber structures, bowlpottery etc. The authors conclude that these elements of Neolithic life first appear in theGreater Thames estuary during the 41st century cal BC. From there the process ofNeolithisation spreads slowly into southern and eastern England, then west into Walesand the Marches by 3700 cal BC. The early dates from domesticated cattle bones atFerriter’s Cove, Co. Kerry, have been taken to suggest that Neolithic migrants hadunsuccessfully attempted to colonise Ireland, ahead of the later Thames estuary venture.
The remarkably early dates from the Magheraboy, Co. Sligo, enclosure (40 th to39th centuries cal BC) are difficult to accommodate within the available models. Not onlyare they significantly earlier than the English examples, but they predate the emergenceof other Neolithic practices on the island from the late 39th to early 38th centuries cal BC.Based on the totality of the evidence, it is argued that the Neolithic way of life was firstintroduced to Britain and Ireland from the near Continent. Similarities in bone andcereal assemblages suggest a number of possible points of origin, including: Brittany,Normandy, Calais, the Paris Basin, Flanders, and the southern Netherlands. One of themodels advanced suggests that numerous small-scale migrations occurred frommultiple departure points, over the course of 200-300 years. Another proposes a near-simultaneous, large-scale emigration from the Continent, while a third is a combinationof the two with a small number of pioneers, followed by larger numbers over time. Whilethe authors examine all of these scenarios in detail, their preferred explanation is of arelatively small ‘founder pool’ of migrants crossing from the Calais region into theThames estuary and south-eastern England. Rather than a large-scale influx of people,the authors argue for rapid acculturation of the native population, especially from the39th century cal BC; though they do allow for further waves of Continental migrantscoming across the English Channel.Chapter 13, ‘Carbon and nitrogen stable isotope values of animals and humans fromcausewayed enclosures’ (Hamilton, & Hedges) was, essentially, a sub-project within thegreater whole. The aims of this work were to document isotopic variation as thoroughlyas possible; to measure the average range of human δ 15N values from causewayedenclosures and compare them to the available data from chambered tombs; and tomeasure the differences in human and animal δ15N values. The authors conclude thatresults from the causewayed enclosures fit the emerging pattern for the whole of theNeolithic in southern Britain. Analysis of the animal remains indicated that the valuesfor cattle, sheep, and pig differ consistently across all sites. In particular, pigs showedelevated δ13C values, which is interpreted as evidence for foddering in wildwoodresources. Pigs also displayed slightly elevated δ 15N values relative to cattle and sheep,but not of the order present in later assemblages. This is taken to suggest that a differentmanagement regime was in place during the Early Neolithic. Analysis of the human-faunal difference is interpreted as evidence for a high proportion of animal protein(either meat or dairy) in the diet. Chapter 14, ‘Neolithic narratives: British and Irishenclosures in their timescapes’ (Bayliss, Healy, Whittle, & Cooney) attempts to ‘weavenarratives out of the chronological threads spun from the models constructed in thecourse of the regional discussions’. This is an extremely complex and involved chapterthat, I am sure, will be the basis for discussion and debate for some time to come. Thecentral conclusion of the chapter is that while ‘all models are wrong’ the intensive workon the Bayesian models and various alternative approaches, all showing similar results,may reassure us that the results are not ‘importantly wrong’. Even so, the authors makeit explicit that the models presented here are not definitive, but are their preferredinterpretations, based on the quality of the data available. Chapter 15, ‘Gathering time:the social dynamics of change’ (Whittle, Bayliss, & Healy) attempts to bring the evidencefor the entire range of Early Neolithic life experiences together, moving beyond theenclosures to the transfer of artefacts and the husbandry and slaughter of livestock etc.In particular, the new chronological framework that the project has revealed allows a
series of different timescales to be examined. These include the scales of generation,lifetime, active social memory, and longer-term structures like myth and story. Finally,the authors suggest that we are now at a point where the term ‘prehistory’ may beusefully abandoned. While terms such as ‘(pre)history’, and ‘protohistorie’ are rejected,alternative titles are proposed: ‘total history’, ‘absolute history’, and ‘total archaeology’.A final appendix, ‘Some unanswered research questions for southern British enclosures’(Healy, Whittle, & Bayliss) give a succinct list of questions, the answers to which wouldgreatly add to our understanding of the individual sites mentioned, and aid in furtherrefining the author’s models.The debate as to the function of causewayed enclosures has been around for some timeand the authors examine the possibilities, from places of assembly to defuse tensionsbetween rival groups keen to exploit the same limited resources, to places of politicaland dynastic ritual where access was granted only to a privileged few. However, noamount of dates and chronological refinements can elucidate the meanings that thesesites had to their creators and those who witnessed and partook in the ceremoniescarried out there. Nonetheless, analysis of the dates does suggest that they wereconstructed in three defined phases from an experimental start where a range of shapesand sizes of enclosures were attempted. This was followed by a rapid expansion of thenumbers of enclosures being constructed, increasingly to a common template. Finally,small communities built their own enclosures to express their own independentidentities. The authors admit that the precision with which we may now examine thecommencement of the causewayed enclosure phenomenon is not replicated in how weunderstand their demise. They appear to have been abandoned, but not whollyforgotten. They frequently survived in the landscape, sometimes reused and with theirditches recut. As I said at the beginning, the importance of this work is not simply that ithas forced a large-scale rewriting of the process of Neolithisation and presented us witha fine-grained chronology of the period, but that it now serves as a template for otherresearchers to follow. Whether they study other geographical areas or different timeperiods, Gathering Time now shows the way forward to us all. Notes: 1) Robert M Chapple wishes toacknowledge the financial assistance provided under the Built Heritage element of theEnvironment Fund by the Department of Arts, Heritage and the Gaeltacht towardsthe Irish Radiocarbon & Dendrochronological Dates project [IR&DD Facebook Page].2) I am indebted to Christopher Catling’s (2011) review of Gathering Time for helpingme make sense of this vast amount of data.References:Catling, C. 2011 ‘Gathering Time: The Second Radiocarbon Revolution’ CurrentArchaeology 259, 12-19.
Chapple, R. M. 2008 ‘The excavation of Early Neolithic and Early Bronze Age sites atOakgrove, Gransha, county Londonderry’ Ulster Journal of Archaeology (3rd Series) 67,22-59.