Pediplain

A pediplain is an extensive plain formed by the coalescence of pediments, from the Latin pes for foot. It develops through a process called pediplanation, in which rock scarps retreat over geological time in arid and semi-arid climates and the pediments at their base migrate and widen, so the landscape lowers mainly through backward erosion of slopes rather than downward erosion of the surface. Geologist Lester Charles King described the process in his 1942 book South African Scenery, presenting it as an alternative to W. M. Davis's theory of peneplanation; a pediplain can carry a series of very gentle concave slopes and can form at more than one elevation without all of it grading down to a single base level, which distinguishes it from a classic peneplain.