‘How is it we can see these sites from the air?’
The differential growth that occurs between crops or grasses growing on quick-draining sand and gravel and those on the moisture-retaining soil that fills ditches and post-holes is a boon for archaeologists. Those over the rich reservoir of moisture retain their colour and continue growing, whereas those over quick-draining sub-soils are parched and stunted.
When conditions are at an optimum, such as during long, hot, dry summers, these differences are often visible from the air as patterns that excavation generally allows us to assign to particular periods of history.
The photograph above, taken by J.K.S. St. Joseph on 9 July 1949 records the sites discovery. West is toward the top of this image and the Kirknewton road can be seen on the left. Three years later the photograph was included in a publication entitled ‘Monastic Sites from the Air’ (Knowles, D and St. Joseph, J.K.S. Cambridge University Press 1952) an indicator of the difficulties in identifying Anglo Saxon settlement at this time.
Since 1949 the site has been photographed from the air many times at different times during the year and when under different crops and conditions of drought. Since the 1980’s an exceptionally fine sequence of photographs have been obtained by Tim Gates, and most recently the Gefrin Trust has been fortunate in obtaining some exceptionally crisp and technically detailed photographs through the LiDAR (Light Detection and ranging) technique.
The image below was taken in 2006 to accompany the LiDAR survey and is particularly interesting as it clearly shows markings in the field to the south of the road. On the far right of the image can be seen the circular impression of the neolithic henge. The marks of a number of buildings and enclosures can be clearly identified.
The Trust is currently assembling a catalogue of all aerial photographs of the site; a comprehensive record of the interplay between various crops and weather conditions that indicates what geological and archaeological features might lie beneath the topsoil. The Trust is also well positioned to take new aerial photographs as the conditions recommend.