The early Mesolithic colonisation of Britain: preliminary results Chantal Conneller1 & Tom Higham2 1

Department of Archaeology, SALC, University of Manchester, Oxford Rd, Manchester, M13 9PL, UK. chantal.conneller@manchester.ac.uk 2

Oxford Radiocarbon Accelerator Unit, RLAHA, Dyson Perrins Building, University of Oxford, Oxford, OX1 3QY, UK.

Abstract

This paper presents the preliminary results of a project which aims to elucidate the chronology of the first two millennia of the Mesolithic. We focus here on just one aspect of this project, the issue of continuity or hiatus between the terminal Upper Palaeolithic Long Blade or Belloisian industries and the earliest Mesolithic. We argue that preliminary results indicate a hiatus between the two occupations, possibly relating to the climatic downturn of the Preboreal Oscillation. It appears that Mesolithic groups only became established after this event, when woodlands became more securely established in southern Britain.

Introduction

The Mesolithic as a whole is poorly dated. The most recent assessment of the early Mesolithic by Reynier (2005) for example identified only 20 reliable dates from ten sites. This lacuna appears even more acute due to the advances made recently in producing a refined chronology for both the late Upper Palaeolithic (Jacobi & Higham 2009, 2011; Jacobi et al. 2009) and the early Neolithic (Whittle et al. 2011). The poor chronology we currently have for the Mesolithic has serious consequences: a concomitant poor knowledge of typochronology means that the Mesolithic is simply divided into early and late phases. As a result the Mesolithic becomes timeless and unchanging; a contrast to the dynamic succeeding Neolithic and preceding Palaeolithic. This reinforces old ideas of the Mesolithic as a period of stagnation, or even of degeneration.

This paper reports on the results of the first phase of a project, The Early Mesolithic Colonisation of Britain, initiated by Roger and continuing in his absence, which aims to remedy this deficit. The project is primarily focused on the first two millennia of the Holocene and involves the reanalysis of several important, but poorly dated early Mesolithic sites, as well as a reassessment of existing dates for the Mesolithic. Its aims are four-fold:

1. To elucidate the start of the early Mesolithic and its relationship with the preceding Long Blade occupation.

2. To isolate and date the different ‘facies’ of the Early Mesolithic.

3. To understand changing patterns of faunal availability and exploitation in the Preboreal and Boreal.

4. To understand the transition between early and late Mesolithic.

In this paper we will address just the first of these aims and investigate the nature of the transition between the Terminal Palaeolithic ‘Long Blade’ occupation of Britain and the earliest Mesolithic industries. This was an issue close to Roger’s heart, and one he addressed at the British Museum Palaeolithic and

Mesolithic conference in 2006 through a discussion of the stratigraphy of the site of Flixton II, North Yorkshire. Here he argued for a hiatus between the Upper Palaeolithic horse butchery event represented at the site and the earliest Mesolithic in the region. This hiatus, he argued, spanned the Preboreal Oscillation (PBO), an Early Holocene cold event dated to c. 11400-11250 cal BP. This contribution will attempt to augment Roger’s analysis through discussion of this issue in two separate areas of the country: in the south, using evidence from sites along the Thames tributaries of the rivers Kennet and Colne; and in the north, drawing upon dates from sites in the Vale of Pickering, North Yorkshire.

Climatic fluctuations of the late Pleistocene and early Holocene

The rapid warming that marked the end of the Younger Dryas, where temperatures rose from glacial levels to those similar to the present day in less than 50 years (Taylor et al. 1993; Alley 2000), put into motion major changes in north-west European vegetation and faunal sequences. Open tundra environments, populated by herds of horse and reindeer, were replaced with birch/pine woodlands, inhabited by forest dwelling herbivores, such as red deer, roe deer, elk, pig and aurochs, transforming the environment of late Pleistocene hunters. While the rapid end to the Younger Dryas has been indicated by ice core data, the presence of a radiocarbon plateau at 10,000 BP had precluded a precise understanding of human responses to this change.

Perhaps considered less widely are the potential effects on human populations of the early Holocene PBO. The PBO was probably caused by a meltwater pulse disrupting the North Atlantic Deep Water circulation system (Bjorck et al. 1997; Fisher et al. 2002). Its effects have been glimpsed in the GRIP ice core (Johnson et al. 1992) and in sedimentary and palynological records in northern central Europe (Bjorck et al. 1997; van der Plicht et al. 2004). The PBO is associated in particular with cold winters, which were of sufficient severity to

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lead to a re-expansion of herbaceous taxa at the expense of birch/pine forests in northwest Germany and the Netherlands at around 11,430-11,350 cal BP (Behre 1967; Usinger 2004; van der Plicht et al. 2004; Bos et al. 2007). Areas newly colonised by forests in the initial Holocene warming seem to have been particularly vulnerable to this change (van der Plicht et al. 2004).

The archaeology of the Pleistocene/Holocene transition

The severity of the Younger Dryas was such that parts of northern Europe that had been previously occupied during the late glacial interstadial (e.g. the northern Netherlands (Stapert 2000) and Britain) were abandoned. However other areas saw continuity, with Ahrensburgian industries, characterised by small tanged points, present in Benelux, Germany and parts of southern Scandinavia. The exact span of the Ahresburgian is not well understood and many dates, such as those for the classic Ahresburgian reindeer kill site of Stellmoor, seem to cluster towards the end of the Younger Dryas (Weber et al. 2011), perhaps suggesting more permanent occupation of northern regions at the end of the period. Towards the Pleistocene/ Holocene transition, a hypothesised increase in simple obliquely blunted points (Zonhoven points) in these tanged point assemblages has led them to be termed epi-Ahrensburgian (Gob 1991; Johanssen & Stapert 2000), though some would dispute this patterning (e.g. Vermeersch 2008, 2011).

The relationship between the Ahrensburgian, the epi-Ahrensburgian and the northern French/southern English Long Blade or Belloisian industry of the Pleistocene/Holocene transition has been debated. Long blade sites are characterised by the presence of bruised blades (lames mâchurées) and large blades greater than 12 cm (Barton 1998); formal tools are rare. There are broad similarities between the Ahrensburgian and Long Blade industries (Valentin 2006), in the presence of giant blades (riesenklingen) and lames mâchurées in the Ahresburgian, and Ahrensburgian or Zonhoven points in Long Blade assemblages. As a result it has been suggested that Long Blade sites represent a workshop facies of the Ahrensburgian (Gob 1991, 229) and that subsuming the Bellosian under the broad term the epi-Ahrensburgian would be appropriate (Fagnart 2009). Also present in northern Europe are occasional Laborian assemblages, characterised by basally truncated backed points (Malaurie points) and narrow backed points (Blanchère points); these are more typical of central and southwestern France. Both Malaurie and Blanchère points are also occasionally present as elements in some Long Blade and Ahrensburgian collections (Valentin 2008).

The question of population continuity or hiatus between the Ahrensburgian/Epi-Ahrensburgian sensu lato and the Mesolithic, a question that might also be

framed as one of adaption versus migration in response to the major climatic changes of the Pleistocene/Holocene transition, has been a major point of discussion over the past decade (e.g. Terberger & Erikson 2004; Strauss & Goebel 2011). Precisely what effect these major climatic and environmental changes would have had on the inhabitants of northern Europe has implications for understanding the adaptability or resilience of late Pleistocene hunters. Though arguments have been made for cultural continuity across the immediate period of the transition in Poland (Kobusiewicz 2004), more generally the profound climatic and environmental changes that took place have been seen to fundamentally affect the lives of northern European populations. It has been argued that the northwards movement of the herds on which people depended would have necessitated a response, with groups either forced to migrate and follow their prey or adapt to the newly forested environments (Terberger & Erikson 2004).

Many authors have suggested that the archaeological record indicates the migration of Palaeolithic groups, with the tanged point assemblages of early Holocene Norway and Sweden, the Fosna and Hensbacka, argued to represent the descendents of Ahrensburgian reindeer hunters, forced north by ameliorating climates and the northerly migration of their prey (Johansen & Stapert 2000, 84; Gramsch 2004). The landscapes abandoned by Ahrensburgian groups would then be colonised by hunters from the south bringing with them Mesolithic toolkits (Gramsch 2004). Other researchers have favoured a narrative of population continuity and adaption to changing circumstances - the presence of Zonhoven points in Ahrensburgian and epi-Ahrensburgian assemblages and the employment of the microburin technique on occasion to make some Ahrensburgian small tanged points (Ballin & Savile 2003) has been argued to represent the precursors of early Mesolithic toolkits and technologies (Gob 1991; Terberger 2004).

Often these arguments are regionally specific, so, for example, immigration of new peoples is an obvious process in areas that witnessed abandonment during the Younger Dryas. A mixture of strategies may also have occurred in particular parts of Europe, with some groups staying put, while their neighbours migrated. However there are also disagreements about how to interpret the available evidence, with both continuity and discontinuity variously claimed for Benelux (Vermeersch 2008; Vermeersch 2011 contra Crombé et al. 2011) and northern Germany (Terberger 2004 contra Gramsch 2004).

In the British Isles poor dating of sites belonging to this period has precluded an assessment of the issue. The presence of a Long Blade occupation, concentrated along the river valleys of southern England, but extending into the midlands (Cooper 2006) and northern England, has been assumed, on the basis of the radiocarbon dates from Three Ways Wharf (Lewis 2011),

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to date to the Pleistocene/Holocene transition. Early estimates from the Mesolithic site of Thatcham III of 10,370 ± 120 BP (10,631-9832 BC) and 10,030 ± 170 BP (10,226-9221 BC) (Wymer 1962) have muddied the issue, suggesting to some an early date for Mesolithic-type industries (e.g. Smith 1991). More recent researchers (e.g. Reynier 2005) have rejected the Thatcham III dates as anomalous as they are based on bulked samples including hazelnuts, which were not present in the local vegetation this early.

Barton (1991, 1998) has highlighted elements of both technological change and continuity in Britain across the transition, though has not explicitly addressed how this may relate to population dynamics, no doubt due to the paucity of evidence. He suggests major technological changes between Long Blade and Early Mesolithic assemblages may be related to adaption to forested environments (Barton 1991), but also highlights similarities between microliths in Ahrensburgian assemblages and those from British early Mesolithic sites such as Kelling Heath (Barton 1998). Similarly Dumont (1997), in her preliminary study of British Long Blade and Early Mesolithic assemblages, notes both technological change and some typological continuity. These she suggests, may be related to major changes at this time, but believes evidence is currently lacking to produce definite conclusions.

Currently the issue of population continuity or hiatus across the Pleistocene/Holocene boundary in Britain – as in many other parts of Europe – is thus undetermined. The paucity of reliable Terminal Palaeolithic/preboreal Mesolithic radiocarbon dates and the presence of radiocarbon plateaux at 10,000 BP and 9600 BP complicate the issue, making it difficult to understand the nature of human responses to environmental change. In the remainder of this paper we will offer some preliminary thoughts on the continuity/hiatus question, bringing together the latest dates for Long Blade and early Mesolithic sites in two key regions of Britain.

The Vale of Pickering and the Thames region

Two regions were selected to investigate the archaeology of the Pleistocene/Holocene transition, the Vale of Pickering in the north of England and, in the south, the Thames tributaries (effectively, given the number of sites with reliable dates, the rivers Colne and Kennet). These areas both have the advantages of a long history of research and containing a number of the better-dated sites of Long Blade and Early Mesolithic Age (Fig. 1).

The Vale of Pickering was first investigated by John Moore in the 1940s (Moore 1950). Amongst the many sites he discovered is the Palaeolithic horse butchery site of Flixton II (Moore 1954). The Vale of Pickering is best known for the Early Mesolithic site of Star Carr (Clark

1954), also initially discovered by Moore and one of the few reasonably well-dated Mesolithic sites in Britain. Further Long Blade and Mesolithic sites in the Vale of Pickering have come to light through the work of Tim Schadla-Hall and the Vale of Pickering Research Trust (Conneller & Schadla-Hall 2003). Of the sites uncovered in this work, the Long Blade site at Seamer L and the Mesolithic occupations of Seamer C and K are included in this analysis.

Figure 1. Location of sites.

In the south, Mesolithic material has been known since the start of the twentieth century in the Colne Valley. Much of this was discovered during gravel extraction and was poorly recorded (Lacaille 1964). More recently, work in advance of development at Three Ways Wharf has yielded radiocarbon dates associated with both Long Blade and Early Mesolithic occupations. Further to the west, the Kennet Valley preserves a large concentration of Mesolithic and Long Blade sites. Excavations at the Thatcham Complex (sites I-V) by John Wymer were undertaken between 1958 and 1961 (Wymer 1962). As a well known site with good organic preservation, several radiocarbon estimates have been obtained for this complex, mainly on material from the wetland areas, sites IV and V (Reynier 2005). Dates have also been obtained for sites excavated in developer-funded contexts at Thatcham Sewage Works (Healy et al. 1992) and Faraday Road (Ellis et al. 2003) and also a site excavated by members of the Newbury Museum Research Group at Greenham Dairy Farm. Though numerous Early Mesolithic and three Long Blade sites are also known from the upper reaches of the Kennet, unfortunately organic remains are rarely preserved in this area, and radiocarbon dates from the early Mesolithic site of Wawcott XXX appear anomalous (Froom 1976, 2005, 2012).

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Methods

In this paper, we draw upon three main sources of evidence, comprising both extant and new radiocarbon dates. New estimates are available for humanly modified horse bones associated with Long Blade occupations from the two regions through sampling undertaken by Roger himself. New early Mesolithic dates are also present as part of the pilot project for the Early Mesolithic Colonisation of Britain project. Finally the existing corpus of Long Blade and Early Mesolithic radiocarbon dates were collated and assessed for reliability.

Dates on humanly modified horse (Long Blade occupation)

A small number of reliable estimates for Long Blade occupations are available, all from humanly modified horse bones. The majority of these derive from the Flixton II horse butchery site. Several estimates were obtained by Laura Kaagan (2000) as part of her doctoral work; additional material from the site was sampled by Roger. The dates from Flixton II are extremely inconsistent, ranging from 10160-8249 BC, most likely due to humic acid contamination. These complex molecules, under the right depositional conditions, will bind and cross link to the collagen molecule, becoming very difficult to remove. One method that does break these bonds is the hydrolysis of the collagen into its amino acids. The Oxford lab has developed a novel method of then separating the amino acids using high performance liquid chromatography (HPLC). We tested collagen from a horse left astragalus from Flixton II that produced a seemingly too modern radiocarbon age of 9,290 ± 45 BP (OxA-21,175) (8693-8346 BC) ; hydroxyproline (Hyp) from the remaining collagen was extracted and dated by AMS (Marom et al. forthcoming). The Hyp fraction yielded an estimate of 10,155 ± 55 BP (10,110-9466 BC). This determination is reliable, since only the amino acid from the bone is being dated and it permits an assessment of the existing dates for the site. It appears that the most reliable dates are those treated with an ion-exchange column as part of the pre-treatment (with the exception of sample OxA-6329, which gave an age estimate of 9,160 ± 80 BP/8599-8249 BC). Ion exchange was routinely conducted in the past at the ORAU before being replaced by ultrafiltration (Hedges & Law 1989) due to problems with column bleed in low collagen yielding samples producing inaccurate dates. The recent ORAU results confirm the fact that ultrafiltration can be less efficient in decontaminating high molecular weight humic contaminated samples than those treated using single amino acid and ion-exchange protocols.

An additional estimate of 10,025 ± 45 BP (OxA-19511) (9864-9404 BC) from the Vale of Pickering comes from Seamer L, on a cluster of horse bones in a layer of peaty sand associated with a Long Blade knapping scatter (Conneller 2007). An estimate of 10160 ± 90 BP (OxA-6330) (10184-9406 BC) on horse from the site of Barry’s Island, though seemingly accurate, derives from a redeposited sand lens, and without confirmation of human modification it has not been included in the analysis.

In southern England, three dates on horse (probably a single animal) are available, all associated with Long Blade scatter A at the site of Three Ways Wharf, Uxbridge (Lewis 2011). Two of these are older estimates, sampled in the 1980s. OxA-1902 was re-dated as part of Roger’s horse project (OxA-18702) and, with a much smaller standard deviation, is the most precise estimate for the site.

New Mesolithic dates

The analysis also includes new Mesolithic dates. Four sites were selected for re-dating in the first phase of the Early Mesolithic Colonisation of Britain project. These are Thatcham III and V in Berkshire and Seamer C and K in North Yorkshire. Samples were preferentially selected to test the potential of cut-marked bone (some of which has been treated with PVA) from dryland contexts for understanding sites of this date. The trend to date hazelnuts, while producing excellent results, cannot date Preboreal contexts that predate the hazel rise (and thus the timing of the start of the Mesolithic); thus bone rather than hazel was the main focus of the project. The Thatcham samples were additionally selected to test the reliability of the old dates by using newer ultrafiltration methods, and to create a chronology for marl accumulation (and associated artefacts scattered throughout) at site V.

Wymer’s Thatcham sites are numbered I-V: sites I and III represent a continuous scatter of debris along a gravel terrace and into the adjacent wetland (IV and V). Thatcham III is the densest area of occupation and contains evidence for both Star Carr type and Deepcar type material (Reynier 2005). Attempts to date cut-marked fauna from site III have previously failed due to low collagen yield (Hedges et al. 1988, 294). The only reasonable estimate for the occupation at Thatcham III comes from resin adhering to an unretouched flake which yielded an estimate of 9200 ± 90 BP (OxA-2848) (8636-8261 BC) (Roberts et al. 1998).

Two samples of cut-marked bone from Thatcham III were selected for sampling as part of this project (Table 1). These unfortunately failed due to insufficient collagen. Thatcham III is a large and complex site and additional dates on alternative materials or using alternative methods for dealing with low collagen yield are needed to unravel its complexity.

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Table 1. Material sampled as part of The Early Mesolithic Colonisation of Britain project.

Site Lab no Sample id. Sample Date BP δC13 Calibrated date

Seamer C ARC83.5004

Bos primigenius, L distal metacarpal Marrow fracture

Failed : Low collagen yield

Seamer C OxA-26541 ARC81.5581 Bos primigenius, R distal tibia Marrow fracture

Failed : Low collagen yield

-20.59

Seamer C OxA-26542 ARC79.5428 Elk/auroch sized Shaft fragment One end burnt

9340±45

-22.41

8740-8470BC

Seamer K

OxA-26543 ARC85.5134 Cervus elaphus, Marrow fracture

10015 ± 50 Too old – pva contamination

-21.83

Seamer K OxA-26544 ARC84.5021 Cervus elaphus, L tibia, Marrow fracture

9990 ± 55 Too old – pva contamination

-22.57

Thatcham III

ARC70.3016

Cervus elaphus, Metacarpal, Marrow fracture

Failed : Low collagen yield

Thatcham III

ARC70.3019 Bos primigenius, Metacarpal, Cut marked

Failed : Low collagen yield

Thatcham V, context 2

ARC70.3014 (TV 2)

Sus scrofa, distal L tibia, cut marks

Failed : Low collagen yield

Thatcham V, context 3

OxA-26538 ARC70.3014 (TV 3)

Sus scrofa, midshaft humerus, cut marks

9580 ± 45

-22.38

9177-8791BC

Thatcham V, context 4

OxA-26539 ARC70.3016 (TV 4)

Cervus elaphus, distal humerus

9560 ± 45

-22.81

9151-8771BC

Thatcham V, context 5

OxA-26540 ARC70.3016 (TV 5)

Cervus elaphus, Metatarsal, Marrow split

9675 ± 45

-22.27

9262-8844BC

Recent estimates from the Thatcham wetland areas derive from Reynier’s mid-1990s programme focused on southern English Mesolithic sites (Reynier 2005). He submitted three samples from Thatcham V, which at the time of occupation would have been a small pond which appears to have been the focus of wetland deposition. Reynier’s samples yielded dates of 9155-8455 BC or 9430 ± 100 BP (OxA-5190) and 9196-8623 BC or 9510 ± 90 (OxA-5191) on humanly modified fauna from the base of layer 5 and 9121-8356 BC or 9400 ± 80 BP (OxA-5192) on burnt hazelnuts from layer 2. A further four samples were submitted in the course of the current project, of which three yielded sufficient collagen to produce acceptable dates (Table 1).

In the Vale of Pickering, the Seamer Carr complex of Mesolithic sites, situated on the northern shore of palaeo-lake Flixton, are relatively poorly dated. Though eleven samples have previously been submitted from Seamer C, none has a strong link to an archaeological event and most are bulked samples. A cluster of three estimates centring on 8500 BC are likely to be most reliable, though these cannot be linked to specific

activity zones on a repeatedly re-occupied multi-period site. Three additional samples were submitted as part of the project, of which one was successful (Table 1).

Seamer K, a similarly complex site, has previously yielded two estimates relating to early Mesolithic activity, both in the region of 9000 BC. Two samples, with good links to archaeological events were submitted, yielding estimates of around 9300 BC; these appear too old in comparison to the contexts from which the material derived. This is likely to be because the PVA that these materials were soaked in had not been fully removed during pre-treatment. We plan to re-date these samples using single amino acid methods (Marom et al. forthcoming) to mitigate this problem.

Despite the problems encountered with low collagen yield and contamination due to conservation, which had affected some of the samples, the successful dates, taken in conjunction with the reassessment of existing estimates, can be used to address the key concerns of the project in a preliminary manner.

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Table 2. Reliable Long Blade and Early Mesolithic dates.

Site Lab no. C14 age δC13 Sample type

Three Ways Wharf OxA-1778 10270±100 -21.00 Equus ferus

Flixton II X-2395-14 10155±55 -24.60 Equus ferus

Flixton II OxA-6328 10150±90 -20.20 Equus ferus

Flixton II OxA-6319 10150±80 -20.80 Equus ferus

Flixton II OxA-6318 10090±90 -20.80 Equus ferus

Three Ways Wharf OxA-18702 10060±45 -21.50 Equus ferus

Seamer L OxA-19511 10025±45 -20.7 Equus ferus

Thatcham V OxA-26540 9675±45 -22.27 Cervus elaphus

Star Carr OxA-21237 9585±39 -22.20 Cervus elaphus

Thatcham V OxA-26538 9580±45 22.38 Sus scrofa

Star Carr OxA-21236 9561±38 -21.30 Cervus elaphus

Thatcham V OxA-26539 9560±45 -22.81 Cervus elaphus

Thatcham V OxA-5191 9510±90 -21.80 Cervus elaphus

Star Carr OxA-4799 9500±75 -26.10 Phragmites sp.

Star Carr OxA-21238 9485±38 -22.70 Cervus elaphus

Star Carr OxA-21239 9468±38 -22.60 Cervus elaphus

Thatcham V OxA-5190 9430±100 -22.20 Capreolus capreolus

Faraday Road R-24999/2 9418±60 -23.98 Sus scrofa

Thatcham V OxA-5192 9400±80 -23.30 Corylus

Star Carr OxA-4797 9385±85 -27.70 Phragmites sp.

Star Carr OxA-2343 9350±90 -29.10 Betula

Seamer C OxA-26542 9340±45 -22.41 elk/aurochs size

Three Ways Wharf OxA-5557 9280±110 -21.40 Cervus elaphus

Three Ways Wharf OxA-5558 9265±80 -23.00 Capreolus capreolus

Seamer C CAR-197 9260±90 -26.00 charred plant

Star Carr CAR-926 9240±90 0.00 wood

Thatcham III OxA-2848 9200±90 -28.80 resin

Three Ways Wharf OxA-5559 9200±75 -21.30 Cervus elaphus

Greenham Dairy Farm OxA-5194 9120±80 -23.20 Corylus

Thatcham Sewage works BM-2744 9100±80 -23.30 Corylus

Marsh Benham OxA-5195 8905±80 -23.70 Corylus

Reassessment of existing dates

In addition to the new dates, we compiled a database of extant radiocarbon dates from Early Mesolithic and Long Blade contexts in Britain. This is based on an existing database of Mesolithic and early Neolithic radiocarbon dates from north-west Europe (Weninger et al. 2009), which has been revised and updated and expanded to include Terminal Palaeolithic dates. All existing estimates between 10,500 and 8500 radiocarbon years BP have also been assessed for reliability and the strength of the link between the dated sample and an archaeological event. Reliability was based on sample type, with short-lived samples, such as seeds, twigs, resin, human remains and humanly modified faunal material considered most reliable. Samples with known problems such as low collagen yield, hard water error and known contamination were considered to be problematic. Dates without a strong link to an archaeological event were also set to one side. Some older dates with large standard deviations, though seemingly both reliable and accurate, were not included in the model, as their lack of precision obfuscated the results. Further problems arise when one considers the various pre-treatment methods applied. These are potentially acute problems, especially

when it is considered that many of the bones from these sites have been treated with consolidants, or are of very low collagen yield. Dating these samples is very challenging.

The combination of new dates and reliable existing estimates results in a database of 31 radiocarbon dates from 12 different sites within the two regions (Table 2, Fig. 2). Of these, seven are associated with Long Blade assemblages (from three sites); the remainder are early Mesolithic. The dates are divided almost equally between the two regions, with 16 from the Thames tributaries and 15 from the Vale of Pickering. Star Carr is the best dated site, with eight age estimates judged reliable.

Results

Given the relative paucity of dates for the period and the presence of the 10,000 BP and 9600 BP radiocarbon plateaux, this pilot project offers only tentative conclusions that need to be confirmed both through further sampling of sites included in the project and the inclusion of dates from other regions. As the data currently stands, three potential patterns seem worthy of further investigation:

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Figure 2. Calibrated Long Blade and Early Mesolithic dates from the Vale of Pickering (red) and the Thames tributaries (grey). The Preboreal Oscillation at 11,400 cal BP is marked in blue.

1. There appears to be a gap of several decades

between Long Blade and early Mesolithic occupations in both regions, using dates calibrated at 95% confidence. This is perhaps not surprising for the Vale of Pickering, the location of the most north-westerly Long Blade sites in Europe. The material recovered from this region suggests that these sites probably represent the vestiges of people on the margins of their range (Conneller 2007). This area probably only saw sporadic occupation and might therefore be vulnerable to relatively

small environmental fluctuations. However it seems that there may also have been a hiatus in occupation along the Thames tributaries. At least 15 sites are known along the Thames and its tributaries (presuming the Kennet and Colne are representative of this broader region) and the locality appears to have been a core area of Long Blade settlement. This would suggest a more systematic disappearance from Britain of Long Blade groups prior to the appearance of the earliest Mesolithic industries.

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2. Due to the presence of the 10,000 BP calibration plateau, the span of the Long Blade occupation and its relationship to climatic change is not well understood. The dates currently range from the end of the Younger Dryas and into the initial part of the Holocene. The PBO seems to mark the end of the current span of dates. If this is a real pattern, it may offer further support for Gamble and colleagues’ (2005) hypothesis that climatic deterioration is a more important constraint on human settlement than temperature rise.

3. Early Mesolithic sites appear to post-date the PBO in both areas. This may be less about climatic tolerances per se than the consequences of low temperatures on vegetation and fauna, with the area only appearing attractive to Mesolithic groups once a certain suite of resources were present. There are some suggestions that the PBO resulted in a decline in arboreal pollen in the Vale of Pickering (Mellars & Dark 1998, figure 14.1), with birch/pine woodland developing only by c. 9200 BC. This would perhaps confirm long-standing characterisations of the Mesolithic (in this region at least) as an adaption to forested landscapes.

There is currently little difference between the earliest dates for the northern and southern regions, suggesting two alternative scenarios for routes of colonisation by the first Mesolithic groups. The first would involve a fairly simultaneous colonisation of both northern and southern England by different groups. If this were the case, population movement along the major river systems in the south and along the coast of Doggerland in the north seems likely. Alternatively people may have moved initially into either northern or southern England, spreading throughout the country sufficiently rapidly that the direction of movement cannot currently be distinguished by radiocarbon dating.

Conclusions

This paper offers some preliminary thoughts on the nature of the transition between the Upper Palaeolithic and Early Mesolithic in Britain. There currently appears to be a hiatus between dates for Terminal Palaeolithic Long Blade sites and the earliest Mesolithic evidence. This hiatus includes the Preboreal Oscillation, which may, as Roger originally suggested, be more significant than previously envisaged in influencing human settlement. However this pattern is not currently particularly robust, both because of the presence of radiocarbon plateaux at 10,000 and 9600 BP and because of the paucity of reliable radiocarbon estimates for this period. While the presence of the plateaux will remain a significant issue, further sampling of late Pleistocene and Early Holocene sites will improve our knowledge of the archaeology of this period and our

understanding of human responses to rapid and fluctuating climatic change.

Acknowledgements

Many thanks to the Natural History Museum, and to Richard Sabin and Tracy Heath in particular, for supporting this project and generosity in permitting sampling of their collections. Thanks also to Nick Overton for his help in assessing the material from the Thatcham and Seamer sites. Bernhard Weninger generously made available his database of Mesolithic radiocarbon estimates. The Early Mesolithic Colonisation of Britain project was supported by a grant from the NERC radiocarbon facility (NRCF). We are grateful to the staff of the ORAU, particularly Anat Marom-Rotem.

References

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