Situated on a high plateau of chalk grassland, Fyfield Down displays the best collection of sarsen stones in Britain. Sarsen stones are large boulders of siliceous sandstone that were transported to the area through glacial action during the ice age. Ancient peoples used these stones for building purposes and today they support rare lichen and moss communities. Mapping and excavations have established that settlements were in use here 7,000 years ago. The stones at Averbury were brought from here.