level surfaces in the form of steps along the margins of the highest and most rugged part of mountain areas. The concept of piedmont steps was introduced in the 1920’s by W. Penck, who interpreted them as denudation surfaces of different age that form with the uninterrupted, even uplift of a mountainous region and involvement in the uplift of territory from adjacent regions.
Subsequent investigation has shown that piedmont steps are not characteristic of the external form of mountainous regions. Where multilayer level surfaces do occur, they belong to the mountain relief rather than the piedmont. Therefore, the term “piedmont steps” is inaccurate; it would be more correct to call the formations mountain steps.
Penck’s explanation of the origin of piedmont steps is unsatisfactory because smooth, continuous uplifts of a mountain region cannot be associated with the formation of steps. Multiple denudation surfaces are usually the result of an alternation of periods of rapid uplift of the earth’s crust and periods of relative calm. They sometimes result from the formation of the same denudation surface by tectonic processes that cause different parts to be at different elevations.