Asfordby Mesolithic Site

Making and breaking microliths: A Middle Mesolithic site at Asfordby, Leicestershire

Wayne Jarvis & Lynden Cooper

Introduction

Between 2008 and 2011, archaeological fieldwork ahead of a housing development at Asfordby revealed a lithic scatter in a primary context of locally preserved paleosoil. The dense scatter resulted from the production of flint bladelets used as blanks for microliths. Impact-damaged microliths indicate the re-tooling of hunting weaponry. The site produced a distinctive range of microliths that can be classified as a Honey Hill assemblage type, including obliquely truncated points, backed points, large scalene triangles and points with inverse basal retouch. Such lithic assemblages have a restricted distribution in the English Midlands and East Anglia and are thought to be temporally intermediate between the conventional Early and Late Mesolithic of England.

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The archaeological excavation.

Two hearths were apparent from concentrations of burnt lithics and/or calcined bone, as well as enchanced magnetic susceptibility readings. A series of radiocarbon dates suggest that the east hearth was probably used c.8k cal BC, and the great majority of the lithic scatter was centred around this locus. The west hearth was probably used c.7.7k cal BC but there is scant lithic-producing activity around this area. Later visits to the locale may be indicated by calcined bone dated as late as c.7.3k cal BC and a few diminutive microliths.

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Plan showing distribution of all 3D finds.

General Background

The Asfordby site is situated 3 miles from Melton Mowbray on the north side of the Wreake valley, in north Leicestershire. The Wreake valley is an area of significant Prehistoric archaeology, with other Mesolithic sites known at East Goscote and Eye Kettleby. Initial work at Asfordby included a desk-based assessment, geophysical survey and trial trenching. The trial trenching identified unabraded worked Mesolithic flints from the subsoil in one area. Further work involved excavation by hand of eighteen 1 meter square test-pits through the soils to determine the location and depth of the flintwork. The test-pits identified a dense scatter of Mesolithic flint, with over 1300 lithic artefacts being recovered.

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Every find was given a 3D GPS co-ordinate.

Based on the test-pitting results a 10m square area was targeted for excavation and full 3D recording of finds. This area was excavated by hand in thin spits and by meter square and has produced some 8000 worked flints, burnt bone fragments, charcoal and possible structural evidence with stone settings and post sockets.

Site Stratigraphy

In the site area, the sequence consisted of topsoil, upper subsoil, colluvial deposits, the Mesolithic layer, Mesolithc ‘subsoil’ and drift ‘natural’ in sequence. The buried soil deposits (the colluvia and Mesolithic sequence) below the upper subsoil level only survived in this limited locale of site in what is an infilled hollow at least 20m wide (east-west), more than 80m long and up to 1.5m deep at the south. The survival of these buried soils is due partly to this hollow but also partly due to the absence of (historic) plough truncation in this area with evidence indicating that this area had not been repeatedly ploughed over a long period.

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Soil sequence in the Mesolithic area of the Asfordby site. The plot to the left of the section shows the density of lithics, clearly concentrated within the Mesolithic layer.

 In contrast, ploughing was evidenced from both the geophysical survey and site observations over the rest of the development area, where the plough had produced a truncated sequence of topsoil, subsoil and natural drift. This subsoil in the ploughed area was in part an artefact of cultivation and followed the characteristic medieval ridge and furrow corrugations, with any earlier soil build ups below this level having been truncated. Prehistoric features identified elsewhere on site were sealed below this subsoil level.

Six samples from monoliths were investigated by thin section for soil analysis (R McPhail, Institute of Archaeology, University College London). These indicated that the sequence had been subject to a series of alterations due partly to the seasonal waterlogging of the site. This has produced a discontinuous ironpan and zones of mineralisation and depletion altering and discolouring the soils. Also, bioworking (burrowing), and muddy colluvial formation possibly including trampling of muddy ground occurred. The presence of both larger and smaller anthropogenic (lithic and charcoal) material argues against any kind of sorting or derivation of the deposit, however, indicating a relatively in situ and very localised occupation deposit.

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Soil monolith sampling being carried out.

Site Dating

Under the guidance of Alex Bayliss (English Heritage), eighteen samples of calicned mammal bone were successfully submitted for radiocarbon dating to the Scottish Universities Environmental Research Centre (SUERC) and the Oxford Radiocarbon Accelerator Unit. The calibrated date ranges for the samples were calculated using the maximum intercept method (using OxCal v4.17) and the agreed atmospheric calibration (IntCal09).

The radiocarbon dates from Asfordby clearly fall into a coherent group concentrated on the first half of the eight millennium cal BC relating to the Mesolithic use of the site. The measurements are not statistically consistent though, indicating more than one episode of activity. Bayesian statistical modelling was therefore undertaken, and an initial model that the Mesolithic activity was a continuous period of occupation had good overall agreement. However, it is very unlikely that the site was occupied continuously for many centuries. Episodic visitation is much more likely, and as the results fall into a minimum of five statistically consistent groups, this means that there was a minimum of five discrete episodes of Mesolithic activity. A second model considered the C14 results from the immediate vicinity of the two postulated hearths. Five measurements from the east hearth area are statistically consistent. Thus two relatively discreet episodes of activity associated with the two hearth features can be postulated on both statistical and archaeological spatial grounds. A number of later visits to the site can also be discerned, although specific activities related to these events cannot be identified on the ground.

Dated Mesolithic activity at Asfordby began in BC 8360-8000 and ended in BC 7460-7160. The east hearth was in use between BC 8220-7840 and BC 7960-7530. The west hearth was in use between BC 7920-7600 and BC 7710-7430 and it is 74% probable that the west hearth came into use after activity around the east hearth had ended (all dates here are modelled using Bayesian statisitics, cal BC 95% probability).

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Probability distributions of dates from Asfordby, Kettlebury and Longmoor I. The large square brackets down the left -hand side along with the OxCal keywords define the overall model exactly.

The Lithics

Some 8000 flints were removed by hand excavation while a wet-sieving programme produced copious micro-débitage. The principle activities at the site comprised the production of bladelets, blanks for making microliths. Re-tooling of projectiles can be inferred from a cluster of impact-damaged and broken microliths and evidence for micolith manufacture in the form of numerous microburins. However, some microliths showed usewear traces relating to other activities such as butchery.

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Bladelet cores with opposed platforms. Note the pitting on the example bottom right where the core has been used as a hammerstone.

The assemblage has a distinctive technological and typological profile of a Honey Hill assemblage type. The microliths are dominated by obliquely truncated points, backed points, and points with inverse basal retouch, the latter a defining trait of such assemblages. The microliths show a near-ubiquitous feature in the form of sinstral lateralisation – i.e. they were nearly all retouched on their left hand side. Bladelet production was methodical and comprised reduction from single platform and opposed platform cores, prepared by abrasion of the core front. Ventral stigmata on the bladelets demonstrated that the cores were reduced with a soft stone percussor. However, there was some evidence for a less skilled knapper on site feasibly a child.

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Points with inverse basal retouch from site.
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Non-flint tool from the site.

The Honey Hill assemblage type appears to be a Midland phenomenon but showing some linkage with Horsham sites of southern England, and more distant links with Middle Mesolithic sites of northern France. It is proposed that Honey Hill type sites and the related Horsham sites be termed Middle Mesolithc, reflecting similar developments in north-west Europe. Interestingly the site is broadly contemporary with the site of Howick which has lithic techno-typological characteristics of the Late Mesolithic (geometric microliths and narrow blade technology).

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Mastic surviving on microlith. The residue is a blackened deposit possibly solidified from a liquid. Fatty acids were identified from the residue analysis, but these may be from a plant or animal source (i.e. animal fat or vegetable oil). One possibility is tree sap (e.g. birch) used for a hafting adhesive.

Usewear

A sample of 147 pieces was sent to Adrian Evans at the Lithic Microwear Research Laboratory at the University of Bradford and subject to microscopic analysis. Nine were unused, but sixty-two pieces were in a condition where a use-interpretation could be made. Several were patinated (due to burning or the burial environment), some of which were too burned to a point where analysis was not feasible. Some could be moulded and positives made enabling imaging of otherwise highly reflective areas (see photo). The site may have been a ‘resource procurement location’, with a wide range of maintenance activities also occurring, hide processing and retooling of impact damaged microliths being principle activities, and also meat cutting.

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Scrapper 992. Left – edge of original. Right – replica mould allowing usewear analysis.

Of 107 microliths, thirty-five had diagnostic usewear, including sixteen with impact damage traces, usually associated with projectile use, in the form of arrow tips. ‘Diagnostic’ impact traces usually occur on c.30% of projectile assemblages. The low proportion from Asfordby might indicate that projectile use is not a dominant function of these pieces, and in fact evidence of other uses supports diversity in the utilisation of this tool type. Of the other diagnostic microliths, fifteen have been used for a range of tasks. The second commonest use of these tools after impact is hide/meat cutting – eight microliths were used for butchery or hide preparation activities (cutting, piercing and scraping). Ten microliths that have not been assigned a tool use, or are logged as unused are suggested as being the hafted end of broken tools. Overall, c.9% of the microliths studied showed evidence of hafting which were also broken – clear evidence to suggest retooling activities at the site.

Eight scrapers out of fifteen had use-related wear, all indicating hide working (four worked dry hide, three fresh hide plus one other). Of the eight burins studied only one showed wear traces also for hide cutting.

Fauna and Flora

Sampling of all spoil was carried out for finds retrieval and environmental remains. Environmental samples were taken both as control ‘bulk’ samples and spot samples where any concentrations of charcoal, bone etc. were observed, and all items were located in 3D. Samples were also processed to assess for pollen and mollusc remains. However, no shells survived in the acid soils and the pollen assessment indicated a very low count of pollen survival with only single grains of tree species hazel and pine, and occasional grains of grassland species being reported. Pollen tends to survive only in waterlogged deposits in the region.

Analysis of the charcoal and other charred plant remains from site, also unfortunately indicated a very low rate of survival. Tree species were identified as oak and field maple, the latter of which may be intrusive, however, as this is a species normally associated with a later vegetation sequence. Other rare charred plant remains were most likely seeds mixed into the soil from later animal activity. The total absence of hazelnut is intriguing, as this is almost ubiquitous on Mesolithic sites. It may be that the site was occupied outside the mid-autumn season when these would be harvested.

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Deer phalanx.

Although a large number of animal bone fragments were found on site, these were small pieces, calcined and largely not identifiable beyond saying that both large and medium sized mammals were present. Two identifiable pieces did survive, however, a deer phalanx and pig bone. The significance of the bone assemblage is in the potential it provided for carbon dating.

Conclusion

The earliest site occupation is known to have been around the beginning of the Boreal pollen zone, a time of rapidly ameliorating climate where there is a replacement of pine/birch forest with mixed deciduous woodland (including oak). It is suggested that the lithic technology and tool types on this and other comparable sites reflect novel foraging strategies necessary for settlement in this forest type that appeared at the close of the 9th millennium BC. It is possible that the people using the Honey Hill-type material culture representing colonising human groups infilling the English Midlands landscape at this time.

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