Mount San Antonio, California, USA
(c) 2003 Andrew Alden, licensed to About.com, Inc. (fair use policy)
Mount San Antonio is in the rugged San Gabriel Mountains, ancient deep-seated granitic rocks uplifted by the tectonic forces related to the plate boundary on the San Andreas fault zone.
This view looks straight up Cattle Canyon toward the peak. The stream course begins as an avalanche chute and is filled with great boulders all the way down. These rocks move only occasionally, after a strong cloudburst floods the valley. But even rare events are routine in the vast stretches of geologic time. They only seem rare in terms of our short lifetimes.
