Outcrops of fossiliferous gray to buff sandstone, similar to and contigous with characteristic rocks of the San Diego formation, unconformably overlife unammed eocene sandstones and Miocene? volcanic rocks west of the town of Tijuana in northwestern Baja California, Mexico. Fossils contained in the San Diego Formation indicate environments comparable to those found off San Diego today in a deep-inner sublittorial habitat. A cold water fauna found at the base of the section indicates upwelling of a greater intensity than found to occur today.
