Kimbridge Farm Quarry, Dunbridge, Hampshire
David Bridgland1 and Phil Harding2
1Department of Geography, Durham University
Kimbridge Farm Quarry: geoarchaeological watching brief over lifetime of working quarry.
The collection of artefacts, and recording and analysis of their geological context, at Dunbridge provides a precedent for developer-funding of a geoarchaeological watching brief over the lifetime of a quarry, the work having spanned 17 years of aggregate extraction.
The primary aim was to enhance understanding of the richest Lower Palaeolithic assemblage from Hampshire, amassed from precursors of this quarry in the early 20th century.
Digital terrain modelling was used for 3D-characterisation of the fluvial deposits in the extraction area, revealing two gravel terrace formations: an upper Belbin Formation, which contained most of the archaeological material, and a lower Mottisfont Formation.
Of particular note was the recovery of artefacts demonstrating elements of ‘proto-Levallois’ technology from within the Belbin Formation, while fully developed Levallois was evident across both formations, the Mottisfont Formation having an otherwise relatively sparse Palaeolithic content.
In the final phase of the project, optically stimulated luminescence (OSL) dating was undertaken (see Guidance: table 4), along with mathematical modelling of the terrace sequence within the wider context of the erstwhile Solent River and its tributaries. This led to the proposal of MIS 9b and MIS 8 ages, respectively, for the Belbin and Mottisfont formations, a suggestion in accordance with evidence elsewhere for the earliest Levallois.
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Where: Dunbridge, Hampshire
Palaeolithic period(s): Lower Palaeolithic–early Middle Palaeolithic transition (MIS 9–8)
Type of investigation: Watching brief (working quarry); OSL dating
Methods: Monitoring of quarry faces and ‘reject heaps’; Digital Terrain Modelling; OSL dating
Type(s) of deposit: River Terrace Deposits
Features of interest: Geoarchaeological watching brief across lifetime of working quarry
Post-determination, Pre/during development
- Watching brief
Post-excavation/research dissemination/HER enhancement
- Post-excavation analysis (and reporting)
- Final Report
- Deposit with HER and museum (and Oasis)
- Publication (academic and/or public)
- 1987: Halls Aggregates sought consent for Aggregate extraction, which was granted subject to mitigation
- 1988: Evaluation report by Oxford Archaeological Associates Ltd (Collcutt et al. 1988)
- Dec. 1988: Local Inquiry by Hampshire County Council
- 1989–1990: Watching brief by Wessex Archaeology designed and confirmed
- 1991: Extraction commenced
- June 1991: First watching brief visit by Phil Harding (see Table 1)
- April and June 1992: First visits by geologist David Bridgland (section drawing and sampling)
- February 1993: Interim report published in Quaternary Newsletter (Bridgland and Harding 1993)
- February 1997: Wessex Archaeology adopted a lower frequency of visits
- 1998: Second interim report published (Harding 1998)
- May 2007: Last watching brief visit by Phil Harding as extraction comes to an end
- April 2008: OSL sampling and section recording visit as part of project termination
- December 2008: Application by Wessex Archaeology to ALSF (English Nature) for post-excavation analysis, programme of OSL dating and full reporting of the project
- April 2012: Detailed project report published (online) in Proceedings of the Geologists’ Association (Harding et al. 2012)
- 2014: Synthesised project report published in Proceedings of the Hampshire Field Club Archaeological Society (Harding and Bridgland 2014).
The application by Halls Aggregates (South Coast Limited; now Cemex) for gravel extraction to the south of the SSSI was met with considerable opposition both from local people and archaeologists and was subject to a lengthy planning enquiry.
There was concern amongst the archaeological community that an undisturbed occupation site might be present at Dunbridge, somewhat allayed by the results of the 1987 evaluation (see below), which showed that, although rich, the site probably represented artefacts accumulated within fluvially transported gravel.
The eventual consent carried the constraint that regular developer-funded archaeological and geological monitoring should take place, leading to the watching brief by Wessex Archaeology.
Knowledge of a rich Lower Palaeolithic locality at Dunbridge, in gravel deposited by the River Test (Figure 1), dates back to Dale (1912, 1918), although quarrying began in the second half of the 19th century.
Sections were opened in old workings to the north of the modern quarry as part of the Geological Conservation Review, with the result that part of those areas became a Site of Special Scientific Interest (SSSI) in 1991.
The sections were published in a field guide accompanying a Quaternary Research Association field meeting in 1987 (Bridgland and Harding 1987), although Dunbridge was not visited during that meeting.
Methodology & Research Questions
The watching brief (Table 1) was conducted under a Section 52 agreement. Its novelty meant that there was no prior template for the undertaking. Its aims were to recover artefacts and determine their context, record the geological stratigraphy and understand the chronology of the site. This involved visits to storage piles of >40mm material (‘reject heaps’), which were the source of the majority of the artefacts (Table 2), as well as to the working quarry faces. Important at this stage was the correlation between the location of contemporaneous working and material on the heaps, which was the basis for establishing the context for the finds (within the limitations of such an approach).
Visits were planned initially to be fortnightly, although this was varied based on expediency and was reduced in 1997 to monthly, as extraction and recovery of artefacts had both declined. Survey in the 1990s used measuring tapes and levelling equipment, a total station from 1997, and differential GPS from 2000.
Geological recording took place sporadically (when the sections were deemed optimal), with the geologist visiting on just three occasions (Table 1), when gravel samples were collected. Optically Stimulated Luminescence (OSL) dating and digital terrain modelling, techniques that were unavailable at the start of the project, contributed to post-excavation analysis, along with computer modelling of the river terraces (Harding et al. 2012).
Details of the watching brief are provided in Table 1. Problems encountered involved matching site visits to quarry activity, the latter being subject to the vagaries of aggregate demand, which led to intermittent working and a much longer working life for the quarry than originally envisaged.
Table 1: Summary of Dunbridge watching brief details, showing artefact recovery by type and year, visits and section recording. Modified from Harding et al. (2012). a Visits by archaeologist (A) and geologist (G). b Primarily Mottisfont Formation being worked
|Year (Visitsa)||Sections recorded||Cores||Broken cores/core fragments||Flakes||Scrapers||Handaxes||Débitage||Total|
|1991 (15 - A)||-||0||0||2||0||0||0||2|
|1992 (22 - A & 2 - G)||Jun 25||2||0||8||0||4||0||14|
|1993 (21 - A)||Oct 7||0||0||14||2||5||0||21|
|1994 (22 - A)||-||1||0||17||2||7||1||28|
|1995 (22 - A)||Nov 7||3||0||23||0||16||1||43|
|1996 (19 - A)||-||3||0||32||0||11||0||46|
|1997 (9 - A)||Sept 7||3||1||4||0||5||0||13|
|1998 (8 - A & 1 - G)||May 27||0||0||2||0||2||0||4|
|1999b (10 - A)||Jan 13 & Nov 2||1||0||3||0||1||1||6|
|2000b (9 - A)||-||0||0||3||0||3||0||6|
|2001b (5 - A)||-||1||0||1||0||0||0||2|
|2002b (3 - A)||-||1||0||0||0||3||0||4|
|2003b (2 - A)||-||0||0||0||0||0||0||0|
|2004b (2 - A)||-||0||0||0||0||0||0||0|
|2005b (1 - A)||-||0||0||1||0||0||0||1|
|2006b (3 - A)||-||0||0||3||0||3||0||6|
|2007b (1 - A)||-||0||0||1||0||1||0||2|
As the resource became exhausted Palaeogene bedrock gravels were exploited. Gravel was also imported periodically from other pits in the region for processing, both compromising the value and integrity of collections from the ‘reject heaps’ (coarse material awaiting crushing) that were the source of the majority of the artefacts.
The successful ability to correlate finds with stratigraphy within the quarry relied upon a systematic programme of extraction (Figure 2), over which the watching brief had no direct control.
A problem faced in the dissemination of the project findings was that the British Geological Survey has never differentiated the river terraces of the Test valley in a manner comparable to the terraces of the parent Solent River (e.g. Westaway et al. 2006; Briant and Schwenninger 2009; Briant et al. 2006, 2009), although this was resolved to an extent by the digital terrain modelling undertaken as part of the post-excavation project and by the computer modelling of the terraces by Rob Westaway (in Harding et al. 2012).
Discrepancies between the geological mapping on the adjacent sheets for Winchester (which includes the Kimbridge deposits) and Southampton was a further complication.
Results & Significance
The digital terrain model, compiled from 260 boreholes, supplemented by the section records from the watching brief, characterised the two gravel terrace formations exploited by the quarry, confirming the interpretation by Collcutt et al. (1988).
The upper ‘Belbin’ Formation, which proved to be the source of most of the archaeology, was exploited mainly during the early years of quarrying, such that only the lower ‘Mottisfont’ Formation was available for OSL sampling in 2008. Terrace modelling has placed these as equivalents of the Upper and Lower Warsash terraces of the River Solent (the Test being a left-bank tributary of that now-drowned river), dating from MIS 9b and MIS 8, respectively (Harding et al. 2012; Figure 3; although alternative chronological models have been proposed).
The terrace modelling and OSL dating has provided an integrated chronological model for the deposits and Palaeolithic archaeology of the Solent River and one of its major tributaries, although there are some discrepancies between the terrace modelling and the OSL dating.
A total of 198 artefacts were recovered during the watching brief (Table 2), of which 60 (30%) came from the quarry itself and so could be provenanced with some certainty, despite none being found in situ (Harding and Bridgland 2014).
Handaxes numbered 54, with nine from the quarry; most were of pointed type and in a rolled condition. The artefact distribution, which also includes those from the ‘reject heap’ (see above) shows that 87% come from the footprint of the Belbin Formation. They included three ‘proto-Levallois’ flake cores (Figure 4), characteristic of the Lower–Middle Palaeolithic transition period.
There were also three fully developed Levallois flake cores (Figure 5), one from each of the Belbin and Mottisfont formations and the third of uncertain provenance (Harding et al. 2012). There was also a Levallois flake from the Belbin Formation, in identical condition to the fully developed Levallois cores (Figure 6). This material enables the Dunbridge assemblage to contribute to the debate about the dating of Levallois technique.
The project as a whole allowed the existing collections from Dunbridge to be placed in an improved context; most must clearly come from the Belbin Formation and date from or before MIS 9b.
Figures 4, 5 and 6
Please click on the gallery images to enlarge and see the captions.
- It is perhaps worth noting that the English Heritage-funded Southern Rivers and English Rivers Palaeolithic projects (Wymer 1999) took place as a direct result of the controversy over the Dunbridge quarry (John Wymer, who conducted these surveys, visited the watching brief on four occasions in 1991 (twice), 1995 and 1997; see Table 1)
- The project was envisaged as a precedent for future extraction of archaeologically valuable aggregate
- It did not provide the perfect answer but benefitted from being adaptable
- Its success is evident from the range of publications that arose from it
- It benefitted considerably from the cooperation of the gravel company and its employees
- It has perhaps influenced the monitoring of subsequent workings such as those at Brooksby, Leicestershire (Stephens et al. 2008), and Lynford, Norfolk (Boismier et al. 2012)
- The long lifetime of the project meant that technology improved as it progressed; any repeat would use the later (or further improved) methodology
- Extraction of gravel of Lower–Middle Palaeolithic age is now a considerable rarity; this is perhaps also true for watching briefs comparable to the Kimbridge Farm work.
Table 2: Artefact assemblages from Dunbridge showing recovery during the watching brief from the quarry and washing plant, with comparable figures from the extant collections (cf. Roe 1968). From Harding and Bridgland (2014)
|Artefact||Watching Brief||Roe (1968)|
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