Old landscapes were characterized as the final stage by William Morris Davis (1889) in the River Lifecycle Maturity Scheme. These three images show a cross-section illustration of Erosion, and then two oblique views of different old systems. Plateaus that remain after Erosion of upper mountain layers exhibit this old terrain.
Classification progresses with a mature Stream eroding the landform, until eventually the stage of old Erosion is revealed. Detecting the transition from mature to old is partly subjective. The cycle progresses based on changes in the structure and composition of the landscape.Image from: Stages in the fluvial cycle of Erosion Davis, W.M., 1909: Geographical essays. Boston