Pete Tillman
Big knocker @ golden hour
Radiolarian chert, en.wikipedia.org/wiki/Radiolarite
Incidentally, a "knocker" is likely a Cornish mining term, appropriated by early Calif geologists for these huge outrops that, frustratingly, couldn't be mapped! We're in the Franciscan melange, en.wikipedia.org/wiki/Franciscan_Complex
--where Melange is French for 'unholy mess'! Which it is. These guys were literally bulldozed off the descending Pacific plate as it scraped its way against the overlying N. Am plate. This might look like a clear-cut process in a little diagram you see in a book -- but trust me, Unholy Mess in RL. God knows how far this rock was dragged from wherever it formed: deepwater rocks, formed of the silica skeletons of radiolarian forams. Wikipedia has some of the details, for those interested.
Big knocker @ golden hour
Radiolarian chert, en.wikipedia.org/wiki/Radiolarite
Incidentally, a "knocker" is likely a Cornish mining term, appropriated by early Calif geologists for these huge outrops that, frustratingly, couldn't be mapped! We're in the Franciscan melange, en.wikipedia.org/wiki/Franciscan_Complex
--where Melange is French for 'unholy mess'! Which it is. These guys were literally bulldozed off the descending Pacific plate as it scraped its way against the overlying N. Am plate. This might look like a clear-cut process in a little diagram you see in a book -- but trust me, Unholy Mess in RL. God knows how far this rock was dragged from wherever it formed: deepwater rocks, formed of the silica skeletons of radiolarian forams. Wikipedia has some of the details, for those interested.