ABSTRACT
Most modern soils are developed on top of other superficial deposits, which are either transported or residual. Transported superficial deposits are formed of rock debris which has been carried by some natural agent from where it was formed by weathering and erosion to where it now occurs. Erosion by ice, and deposition of superficial deposits from it, are processes limited geographically at the present day to arctic regions and to very high mountains. Head deposits are superficial accumulations which have usually been moved by solifluxion, and they are a type of drift often formed in periglacial conditions. Where a near-horizontal, strong, rigid layer, such as a bed of sandstone or limestone, rests on clays, superficial movement may produce cambering. Limestone cliffs may also suffer some erosion by solution of the rock in water. Flat, featureless, often poorly drained ground usually indicates that the area has been ponded and that deposits have been laid down in standing waters.
