Jim West of CVAHS writes:
CAGG teamed up with the Chess Valley Archaeological and Historical Society (CVAHS) in July 2014 to undertake surveys near two Roman villas at Sarratt and Latimer. In mid-September the CVAHS did some further work near the Latimer villa site using resistance and GPR equipment; the latter was operated by Ralph Potter (West Essex Archaeological Group) who kindly agreed to make the trek into Bucks,
The results from the surveys using these sensors are shown in the following images.
The four GPR images show the reflected radar from progressively deeper distances from the surface. The approximate depths are 360-420, 540-630, 720-840 and 900-1050mm for images GPR 2, 3, 4 and 5 respectively.
Image GPR 2 shows the line of the public footpath running diagonally SW – NE; there is evidence of the path in the first three images but why should it leave a trace more than half a metre down? One conjecture is that the field surface was lower when the path was established several centuries ago. The GPR images contain no evidence of Roman structures and neither do the magnetometry or resistance images; the GPR survey are has been overlaid onto them to help comparison.
The magnetometry image does show the path and a few strong anomalies but is otherwise unremarkable. Apart from the path, there is no correlation between the GPR and magnetometry images.
The resistance image does not show the path or any other correlation except perhaps the broad V-shaped feature at the top which echoes an absence of features in image GPR 5.
Many thanks to Jim for sending this interesting update to our earlier surveys.