FRANCISCAN ROCKS  The first person to study Mount Diablo geology in depth was a quirky UC Berkeley professor named Andrew Lawson. He found rocks that had emerged from volcanoes in the mid-Pacific. But how did they get on top of a 3,849-foot mountain?

Join us on the TRAIL THROUGH TIME, a series of geology videos presented by the Mount Diablo Interpretive Association in partnership with Save Mount Diablo.