Broom Farm, Soberton Preliminary Report of a Geophysical survey (18th – 19th July 2014) By Carl Raven Liss Archaeological Group (edited by Nick Stoodley) Introduction Liss Archaeological Group were asked by the Meon Valley Saxons Project to carry out a geophysical survey using both magnetometry and resistivity at Broom Farm, Soberton, Hampshire. The survey was carried out in a field lying immediately west of woodland (Bottom Copse). Some years previously a Roman building had been discovered in this wood and the area was designated a Scheduled Ancient Monument (SAM 1001848) (Fig. 2). A recent visit to the field revealed a series of earthworks and a geophysical survey was organised to try to identify the nature of these features and to reveal any underlying archaeology. Magnetometry Twelve 20 x 20 m grid squares, covering an area of 4800 m², were surveyed giving 19200 readings. The results show a number of linear features which are probable ditches filled with debris containing either burnt or metallic material or both (Fig. 1). A number of sub-circular anomalies, measuring roughly 6-7 metres across, were identified in the centre and northern part of the site. In the southern most grids (A1 and B1) an area of high magnetic readings was recorded, probably resulting from large concentrations of ferrous (iron) material. Concentrations of metal often build up around stone features due to fragments of metal breaking off as the plough comes into contact with buried stonework. It may be significant that this area is relatively close to the site of the known building (Fig. 2). Resistivity Nine 20 x 20 m grid squares, covering an area of 3600 m² were surveyed and a total of 14400 readings were taken. A low battery voltage caused by flat batteries resulted in readings that were ‘over-range’ (above 31.5Ω) and are displayed as white blocks in the linear plot (Fig. 3). When the results are displayed in the relief plot the effect of the over-range readings are less apparent (Fig. 4 & 6). The data in this area should however still be regarded as corrupt and invalid. Despite this problem, the overall results show a range of linear features some of which were also identified by magnetometry and thus confirm the accuracy of the survey. Interpretation of anomalies (Fig. 5) A – D linear features, probable ditches containing material also detectable with magnetometer. E – I Linear features, possible walls or ditches not detectable with magnetometer. J – L Area of disturbed ground possible occupation also detectable with magnetometer. M – N Sub-circular features, 6 -7m diameter, possible building base also detectable with magnetometer. O – Q High resistance anomalies also detectable with magnetometer. Summary The geophysical survey successfully identified a complex range of features, mainly consisting of ditches, walls and boundaries that are probably related to the known Roman site. Anomalies E - I appear to act as a barrier containing the areas of disturbance J - L; these two groups are therefore probably contemporary and in all likelihood form part of the villa. Features A - D probably indicate various phases of enclosure ditches and may have demarcated fields that were farmed by the occupants on the villa. High resistance features P and Q are possible pits filled with debris. The sub-circular anomalies (M and N) do not appear to respect E - I and may reflect a different phase of activity on the site. The recovery of a 6th-century Saxon saucer brooch from a location a short distance to the west of the site suggests possible activity in the centuries following the Roman period but it is uncertain whether features M and N are post-Roman in date. Acknowledgements We would like to thank Tom Parker for granting access to the site. The Soberton volunteers are thanked for their assistance, enthusiasm and hard work and we are grateful to Duncan Colin-Jones and David Salmon for arranging the surveys. The Meon Valley Saxons Project are indebted to Liss Archaeological Group for carrying out the geophysical surveys and John Whittaker, Jeff Slingsby and John McNee for providing tuition on metal detecting.