San Pablo Formation

The San Pablo Formation is a Late/Upper Miocene epoch geologic formation of the East Bay region in the San Francisco Bay Area, California.

It is found on the south shore of San Pablo Bay, in western Contra Costa County.

Geology
It is series of marine sandstones with tuffs and ashes. Its subunits, listed alphabetically, are Briones Sandstone, Cierbo Sandstone, Neroly Sandstone, and underlies the Pinole Tuff Formation.

It preserves fossils dating back to the Neogene period.