There's an ancient volcano right in the heart of the San Fran Bay Area and most people here don't know about it. "Round Top" in the Sibley Volcanic Regional Preserve, one of the area's highest peaks, is made up of lava and volcanic debris left over from a 10-million-year-old volcano. During the past 10 million years, massive tectonic forces on the Hayward and Moraga earthquake faults uplifted the Berkeley hills, folding bedrock formations and tilting the Round Top volcano complex on its side. Softer sedimentary rock from the Orinda Formation eroded away, exposing the Round Top volcano. In addition, quarrying in the north half of the preserve has revealed cross sections of the bedrock geology, providing an unsurpassed outdoor laboratory for studying volcanism in the Central Coast Ranges.
OK everybody, you can now let loose the snarky remarks about hoping it blows.