Case Study 1: Lithics Scatters and the Planning Process
Ed Blinkhorn (Archaeology South-East UCL)
Introduction
Analysis of 1280 PPG16 era (1990-2010) interventions which identified Late Upper Palaeolithic or Mesolithic archaeology in England (Blinkhorn 2012; Fig 1.1) underpins this case study, which aims to explore the value, potential and opportunities that lithic scatters present.
The historical approach to lithics at all stages of the planning process will also be discussed. The durability of lithics cements their importance as indicators of prehistoric occupation, especially applicable where impoverished preservation conditions prevail, and they constitute the most reliable distribution of human occupation for earlier prehistory. It is unsurprising, therefore, that lithics overwhelmingly dominate the archaeological record for these periods, and are the most frequently encountered earlier prehistoric evidence class in the commercial sector.
Opportunities
The planning process delivers widespread opportunities and unparalleled access to hitherto unexplored sites and landscapes at scales rarely achievable by the academic or voluntary sectors, notably through large housing developments, quarrying, and infrastructure projects.
Spatial bias generated by planning conditions provides a nationwide archaeological distribution which derives more from economics and less from academic research priorities, perhaps pointing to a more representative picture of settlement/mobility in prehistory.
Larger-scale interventions should not, however, overshadow the value of discrete, high-resolution, and high-impact deposits where they can be identified.
Out of the ordinary discoveries such as the pit burial of eight Mesolithic (Horsham) microliths from Saltwood Tunnel (Devaney 2009; Fig 1.2) or the Final Palaeolithic finds from Nea Farm (Barton et al. 2009) demonstrate the capacity of development-led projects to make valuable contributions to knowledge. However, with only around 3% of interventions returning early prehistoric lithics assemblages of more than 1000 pieces, the value of lithics recovered from any single site is less likely to be as significant as the aggregate value of data generated in any given landscape, or planning authority.
In areas such as Greater London and the East Midlands, lithic scatter distributions have been substantially augmented, leading to riverine-focused datasets. Such progress emphasises the prospection capacity of development-led projects which penetrate superficial geologies and urban land use (Fig 1.3).
Furthermore, the cumulative value of opportunities in landscapes of known significance should not be ignored.
Interventions at Wykeham Quarry (NAA 2004; Fraser et al. 2009), Scarborough (Tabor 2007) and Ling Lane (NAA 1996) broaden both the spatial and temporal scope of the internationally important Late Glacial and Early Holocene landscape in the eastern Vale of Pickering around Star Carr, and a similar effect is noted around Newbury in the Thatcham and Wawcott landscapes. It is notable that in both examples, early consideration and due emphasis has been placed on the potential context of discovery with a focus on the geoarchaeological understanding of significant horizons.
Value/Potential
Commercially derived lithics assemblages have the same potential as those generated by other sectors, and rely upon specialist involvement at the point of discovery to generate value.
Frequently, earlier prehistoric lithics which are reported lack secure stratigraphic provenance due to recovery from non-feature deposits, and the scarcity of geoarchaeological assessment compounds the problem of ascertaining the potential and value of a lithic scatter. The risk is that without an adequately understood context of discovery, lithics recovered from multi-period focused works are reduced to ‘residual’ status.
Additionally, decisions made early on in projects frame the recovery and understanding of a lithic scatter. Feature-focused approaches, used to budget time, scope and costs of excavations, distract from understanding site formation processes and the degree of post-depositional disturbance affecting lithics.
Scientific dating was irregularly applied within the dataset, commissioned on around 7% of interventions, although 11 of the 38 assemblages with more than 1000 pieces were associated with dates. Difficulties in assigning assemblages to periods and sub-periods might be ameliorated with schemes of dating, including luminescence techniques, increasing the value of the assemblage and contributing to a corpus of dated material for refining typochronologies.
Landscape approaches beyond the development site, and broader synthetic works which could enhance understanding at local and regional scales, are essential components of realising the value of excavated lithic scatters.
Publication rates diminish with the size of the assemblage: 60% for those with over 1000 pieces, 56% for those with more than 500, 52% for those over 250, and around 20% for all projects recovering lithics.
Excepting larger projects like the Channel Tunnel Rail Link which have the scope and budget to synthesise data beyond the development impact, mechanisms which draw together diverse data generated by the planning process are few. The state of dissemination is better than might be expected, but synthetic overviews are lacking.
The Planning Process
DBAs
Desk-based assessments (DBAs) form the first stage of the majority of development-led projects, yet are poorly suited to identifying lithic scatter potential. Limited by a short search radius, DBAs can only coarsely map prehistoric discoveries held by the HER, and pre-PPG16 era records are dominated by references to imperfect sources such as Wymer’s (1977) gazetteer.
Crucially, the radial search does not identify contexts of preservation or concealment (eg alluvium), and emphasises standing archaeological features or remains which can be identified from remote mapping. The density of sites within any given area held by the HER ultimately influences fieldwork aims and methods.
Where more visible ploughzone scatters are identified, some degree of truncation can be presumed, though sealed lithic scatters of much greater value are identifiable only through isolation of the preserving context(s), be they features, buried land surfaces, or bodies of sediment.
Greater awareness of regional-scale densities, preferred geologies and landforms guided by the Regional Research Frameworks, and of bias generated by flint collectors and the HER dataset, would enhance the scope of DBAs to recognise areas of potential without immediately adjacent lithic scatters.
Evaluation and excavation
During the 1990s, evaluation of Upper Palaeolithic and Mesolithic sites or lithic scatters saw a move away from wide-interval fieldwalking and test pitting schemes, which were increasingly replaced by machine-excavated trial trenches, already dominant as the chief method of evaluating sites of later periods. The shift may reflect waning interest in determining the presence/absence of lithic sites on the basis of ploughzone evidence, and the widespread frequency of projects with a multi-period focus.
Hey and Lacey’s (2001) study suggests that a 10 per cent trenching sample (of the site surface area) would provide adequate coverage for the Neolithic and Bronze Ages, much more commonly associated with feature-based archaeology. Sampling rates on sites recovering earlier prehistoric archaeology from trial trenching show a marginal increase in the (mean) average, from 3.2 per cent in 1990–1999 to 3.6 per cent in 2000–2009. Test pitting schemes were undertaken at an average coverage of 3.1 per cent, although known deposits were more likely to be targeted.
With trial trenching remaining a dominant field method today, earlier prehistoric archaeology cannot be adequately accounted for at the evaluation stage with such low sample interventions. Given the highly localised nature of high-resolution lithic scatters, those discovered during later phases are likely to incur unexpected financial costs and delays to the development scheme.
Geoarchaeological approaches, primarily palaeoenvironmental exercises on deeper riparian deposits in London, successfully identified four times as many Late Pleistocene/Early Holocene capture points in the period 2000–2009 than in 1990–1999, though the number of interventions remained small, and the methods used were not designed to recover lithics.
The aims and outputs of these studies did not necessarily feed into applying appropriate geoarchaeological methods to later archaeological evaluation strategies of these sites. The investigation of the buried lithic potential of a site requires predominantly closer reading of geological and geophysical data, and deposit modelling, where appropriate, followed by targeted evaluation techniques.
While methods can be better tailored for lithic scatters at sites within and adjacent to known areas of high lithic densities, unanticipated discoveries at the evaluation stage are trickier to manage. It is of high importance to define the limit of Quaternary deposits within interventions across the evaluation area (Pope et al. 2016) – the limit of archaeological potential. In this respect the term ‘natural’ is deceiving and would be best replaced with a geological descriptor.
Emphasis must be placed on understanding the scatter, especially its stratigraphic integrity, as typological assessment by context can be of very limited use in determining spatial potential within an assemblage and across a site. Opportunities to enhance lithic datasets need to be recognised early on in the field, both to benefit efficient progress at a site, and contribute to tailored priorities in Written Schemes of Investigation. As such, lithic scatters can require specialist advice from the outset.
By underestimating the potential contribution of lithic scatters to understanding prehistory, opportunities generated by the planning process can be diminished at every stage of the discovery, assessment and analysis cycle.
Critical three-dimensional data – which highlight degrees of disturbance, in addition to forming the architecture of technological analysis – have been infrequently collected in commercial work at both evaluation and mitigation stages; orientation and dip data were not collected in the cases studied.
Microscopic analysis was carried out on two assemblages from the dataset, recommended but not undertaken on many more, and no residue analysis was commissioned. On well-executed projects, and given favourable preservation conditions, one might expect much higher figures for specialist analyses.
Conclusion
While the majority of the PPG16-era sites within the dataset did not overturn the status quo generated by academia, each project at least contributes to the understanding of local lithic distributions across diverse landscapes and geologies.
Equally, the majority of sites were not anticipated to have an earlier prehistoric component. Many, however, generated nuanced interpretations of assemblages deriving from features and buried land surfaces, capturing the changing Late Upper Palaeolithic and Mesolithic worlds across England and developing new windows into technological diversity and adaptation nationwide.
Key to successful projects were clearly defined site-specific aims which addressed contemporary priorities – and methods appropriate to the geology and anticipated resolution of the lithic scatter. A geoarchaeological approach is preferable, with specialist input into projects from the outset.
References
Barton, R N E, Ford, S, Collcutt, S N, Crowther, J, Macphail, R I, Rhodes, E and Van Gijn, A, 2009 ‘A Final Upper Palaeolithic site at Nea Farm, Somerley, Hampshire and some reflections on the occupation of Britain in the Late Glacial Interstadial’. Quartär 56, 7–35
Blinkhorn, E H, 2012 The Mesolithic and the Planning Process in England. Unpublished PhD thesis, University of York
Devaney, R, 2009 ‘The worked flint from Saltwood Tunnel, Saltwood, Kent’, in Foreman, S (ed), Channel Tunnel Rail Link Section 1. York: Archaeology Data Service.
Fraser, M, Cloutman, E W, Mitchell, W A and Chambers, F M, 2009 Wykeham Quarry Eastern Extension, Vale of Pickering, North Yorkshire. Barnard Castle, Northern Archaeological Associates Ltd Report 09/43
Hey, G and Lacey, M, 2001 Evaluation of Archaeological Decision-Making Processes and Sampling Strategies. Oxford, Oxford Archaeological Unit
Northern Archaeological Associates (NAA) 1996 Seamer Carr Landfill Extension: archaeological evaluation. Barnard Castle, Northern Archaeological Associates Ltd Report 96/53a
Northern Archaeological Associates (NAA) 2004 Wykeham Quarry, Vale of Pickering, Proposed Eastern Extension: survey of deposits in quarry section Q1 and Phase 1 development area WK04. Barnard Castle, Northern Archaeological Associates Ltd Report 04/83
Pope, M, Bates, M, Blinkhorn, E, Conneller, C, Scott, B and Shaw, A, 2016 Excavation and Recording of Lithic Scatters.
Tabor, J, 2007 Scarborough Integrated Transport Scheme, Fieldwork Area A [Cayton Bay], Interim Report. Barnard Castle, Northern Archaeological Associates Ltd Report 07/68
Wymer, J J, 1977 A Gazetteer of Mesolithic Sites in England and Wales. London, Council for British Archaeology Research Report 20
