Report on geophysical survey, 1994.
Introduction
The aim of this survey was to investigate the survival of archaeological features on the moated platform S of the village of Ufton Nervet, Berks (BK12023). The monument survives as an extant alignment of four fishponds with a central moated platform (RCHME earthwork survey, November 1993) which has recently been cleared of over-mature trees and scrub as part of an ongoing management agreement. Despite a degree of erosion to the culverts between the individual fishponds the two larger ponds and the moat itself still retain a considerable amount of water. Currently the site is undergoing a long term programme of conservation works and it is planned to completely clear and replant the moated platform allowing public access to the restored monument. Despite the occurrence of a high concentration of tile and possibly articulated flint nodules observed in the root plates of wind-felled trees on the platform there is little documentary evidence to aid the interpretation of archaeological activity on the site. It was hoped that geophysical survey would elucidate the presence of any substantial building remains and contribute towards the production of on-site interpretation panels for the final presentation of the restored monument.
The site (NGR SU 63 67, Figure 1 ) lies on the edge of the plateau gravel overlying London Clay.
Method
Due to the enclosed nature of the site an earth resistance survey was deemed to be the most appropriate technique to identify buried wall footings.
A survey grid of partial 30m squares was established from a base line running through the centre of the site (see relocation plan, Figure 2) which was positioned in relation to two uniquely labelled oak trees identified as part of the site conservation programme. The area was then surveyed with a Geoscan RM15 resistance meter using the twin electrode configuration with a mobile probe separation of 0.5m. Readings were logged at 1m intervals along successive NS traverses separated by 1m intervals and the data was downloaded to a microcomputer in the field. A contrast enhancing wallis filter (Scollar et al 1990 p175) was used in the final presentation of the data; Plan A shows the raw and processed data displayed in both greytone and traceplot form and Figure 3 shows the raw resistivity data superimposed upon the RCHME earthwork plan.
Results
The raw data demonstrates the wide dynamic range of the data recovered from the moated platform and the concentration of extremely high readings to the W of the site. There is little evidence of linear anomalies and the tentative identification of anomalies associated with former building foundations ( Plan A, plot 5 ) has been obscured by disturbance from felled trees. The strongest evidence for the presence of wall footings exists to the W of the site, although this interpretation is of a highly tentative nature and can only be resolved by trial excavation.
The occurrence of two distinct areas of high resistance readings may well indicate the presence of subsurface building rubble and indeed it was noted in the field that these areas coincided with a concentration of tile scatter on the surface. Correlation of the data with the RCHME earthwork plan is limited to the coincidence of an area of lower resistance immediately N of the inner topographic feature identified in the RCHME plan with a similar low resistance area to the W in the vicinity of the wind-felled root plate containing the articulated flint nodules.
Conclusion
The survey has been hampered by both the key-hole nature of the area available and the inevitable disturbance caused by the wind-felled trees and scrub. The concentration of high resistance readings possibly suggests the presence of building debris. However, the amorphous nature of these anomalies may indicate the poor structural integrity of any surviving remains. It should be noted that despite heavy rainfall immediately prior to the survey, conditions at the site were particularly dry leading to problems associated with high surface contact resistance.
References
Scollar, I, et al 1990 Archaeological Prospecting and Remote Sensing, p175, p349-350, Cambridge.
