Some sites near me:
"Capitola, near Santa Cruz -- The beach is a good site for Pliocene fossil collecting. Clams, snails and sand dollars. They are in the sandstone of the sea cliffs and in the talus that falls on to the beach. Go at low tide, walk a few hundred yards south of the Esplanade at Capitola past the sewage outfall. "
"Jack's Peak near Monterey -- there are fossils of little leaves and shells in shale a hundred yards down the trail from the west parking lot. Also, there's lots of jasper at Point Lobos, 5 miles south of Monterey. "
"Pleasanton, Alameda Co. -- upper Miocene brines sandstone -- Go south on Highway 680 from Pleasant, turn right on to Castled Rd., then left on Pleasanton Sunol Rd. Go approx. 1.2 miles, pass under railroad passover, stop at large hill cut for railroad on left side (east) of road and rail tracks. The whole cut, plus the road banks and down slope to right of road is brines sandstone with huge assemblage of miocene marine fauna. Watch out for trains -- Stay away from the railroad tracks! This is one of the best exposures in area."
Copied from old blog.