Southern California Geology | Pyroclastic Flow Deposits
Extrusive volcanics from violent volcanoes spooted on the coast of Catalina Island including volcaniclastic breccia, ash fall layers and an andesitic lava flow capping the whole thing!
Volcanics are Miocene in age as a result of transtensional movement courtesy of the San Andreas Fault region.
I simply couldn't help myself and jumped in to get a closer look.
Animation by Tanya Atwater via YouTube