The Salisbury Plain chalk massif is part of a system of chalk downlands throughout eastern and southern England formed by the rocks of the Chalk Group; the landscape is underlain by a combination of Lower, Middle and Upper Chalk supporting shallow well drained calcareous silty soils over chalk on slopes and crests. Escarpments are often formed where layers of chalk have been compressed to form a fold, or where the chalk has been faulted, resulting in accelerated erosion along the line of the weakness.