Network Archaeology unpublished report series

Permanent-presence watching brief of the construction of a 250mm diameter gravity feed in July 1999 along the Thames Water Boars Hill Main at Harcourt Hill, Oxford. This was carried out by one archaeologist. The topsoil stripping and pipe-trenching process was carefully monitored, and all archaeological remains investigated and recorded. The project yielded nearly sixty sherds of locally made Romano-British pottery, along with several worked flints and sherds of prehistoric and post-Roman pottery. Excavation of the pipe trench revealed two layers of hillwash containing burnt clay and charcoal flecks but no securely datable material.

The approximate location for each of the four evaluation pits was determined by LKR Design Group prior to the evaluation. Each pit was then positioned accurately in relation to existing college buildings and other fixed points such as roadside kerbs. A mechanical excavator fitted with a lm-wide toothless ditching bucket was used to open the pits. Each pit was approximately 1 m square, and was excavated to a depth of between 650mm and 1100mm. The excavation of each of the geotechnical evaluation pits was monitored by a qualified archaeologist on Friday 22nd June 2001. The spoil from each pit was searched for artefacts. After the excavation of each pit, the sections and base were cleaned, and a photographic, drawn and written record made of all deposits exposed. After the pits had been recorded archaeologically, they were inspected for geotechnical purposes, prior to being backfilled on the 22nd June 2001. RESULTS None of the evaluation pits revealed any deposits of archaeological significance. No artefacts were found except for small quantities of modem brick, pottery and glass in the topsoil, none of which was retained. Each evaluation pit contained a darkish brown sandy loam topsoil, generally 0.3m thick and containing occasional small limestone fragments (less than 0.05m across) and modem artefacts. Below the topsoil in each pit was a pale brown silty sand, at least 0.4m thick and containing moderate quantities oflarger limestone fragments (up to 0.15m across). This 'subsoil' deposit is assumed to be the uppermost weathered surface of the Lincolnshire Limestone geology. CONCLUSION The geotechnical evaluation pits contained nothing of archaeological significance. This suggests that the development site as a whole contains little or no significant archaeology.

The field reconnaissance survey consisted of a visual inspection of all new areas which were not encountered by the proposed pipeline route at the desk based stage of assessment, in order to record extant earthworks, significant soil or vegetative anomalies, the nature of land boundaries, present (and former) land use, visible geology, and general topographical variations. Observations were recorded on pro-forma record sheets. Fieldwalking was carried out by a team of three to four archaeologists walking at 10m spacings within each arable field. Five traverses were walked, centred on the centreline of the proposed pipeline’s working width. This gave a 40m wide survey area, and provided approximately 25% coverage of the ground within this area. Details of each field or land parcel walked (including weather/light conditions, crop type, ground visibility, relief, walkers present) were recorded on pro-forma record sheets. The surveys found D or E grade areas of archaeological potential in twenty-seven of the plots crossed by the proposed route. Most of the D and E grade areas comprise magnetic anomalies of uncertain character, including some pit like and linear features. Some of the anomalies are of likely archaeological significance, whilst others are of uncertain archaeological significance. Some low density scatters of brick and tile, tap slag, and a single sherd of Iron Age pottery may be archaeologically significant. Earthworks representing ponds / quarry pits and former field boundaries were also present. At this stage, the D and E grade sites are felt to have a low archaeological potential, but they are nevertheless significant and should not be dismissed.