Diagram showing the cycle of land-mass denudation in a humid climate. A. In the initial stage relief is slight, drainage poor. B. In early youth, stream valleys are narrow, uplands broad and flat. C. In late youth, valley slopes predominate, but some interstream uplands remain. D. In maturity, the region consists of valley slopes and narrow divides. E. In late maturity, relief is subdued, valley floors broad. F. In old age, a peneplain with monadnocks is formed. G. Uplift of the region brings on a rejuvenation, or second cycle of denudation, shown here to have reached early maturity. Strahler, 1960, p. 251.