A pediplain (from the Latin pes, genitive case pedis, meaning "foot") is an extensive, slightly inclined denudation plain, which is formed under the conditions of arid and semiarid climate on the spot of an eroding mountain range or hilly relief. Formation involves the parallel retreat of slopes from the axis of valleys and connection of the separate sections, or pediments. As for the specific mechanism of the formation of a pediplain, there is no unanimous opinion. It is believed that the primary condition of forming pediplena is the long absence of fault activity, which create inclines, and the fixed attitude of the basis of denudation, which determines the descending development of relief and leveling off under any climatic conditions. It is formed by the erosional works of wind. Mountains are made up of both hard and soft rocks. During erosion by wind, soft rocks are washed out, but harder rocks remained in their place. they formed some uplands and are called inselberg.