In archaeology, earthwork is a general term to describe artificial changes in land level. Earthworks are often known colloquially as 'lumps and bumps'. Earthworks can themselves be archaeological features or they can show features beneath the surface.[1] Earthworks of interest to archaeologists include hillforts, henges, mounds, platform mounds, effigy mounds, enclosures, long barrows, tumuli, ridge and furrow, mottes, round barrows and other tombs.[2] Earthworks from deserted medieval villages can be used to determine the location, size, and layout of lost settlements.
Earthworks can vary in height from a few centimetres to the size of Silbury Hill at 40 metres (130 ft). They can date from the neolithic through to last week. They can stretch for many tens of kilometres, e.g. Offa's Dyke and Antonine Wall, In area they can cover many hectares - for example, Maiden Castle, which is 19 hectares (47 acres).
Shallow earthworks are often more visible as cropmarks or in aerial photographs if taken when the sun is low in the sky and shadows are more pronounced.[3] Similarly, earthworks may be more visible after a frost or a light dusting of snow.[4] An accurate survey of the earthworks can enable them to be interpreted without the need for excavation.[5]