Geology of San Antonio Canyon, California, in relation to ground-water storage

At least two periods of relative stability in the history of the erosion of San Antonio Canyon are indicated by the bench-like features produced by the laterally cutting stream and by the remnants of older alluvium left by the stream when it was cutting at these higher levels. In addition, a much older and probably mature surface is suggested by certain features of the higher ridges and the near-summits of Ontario and San Antonio Mountains.