Preliminary report on the geology of San Nicolas Island, California

The U. S. Geological Survey, at the request of the Director of Naval Petroleum Reserves, undertook a geologic investigation of San Nicolas Island, Ventura County California, in the spring of 1955. This preliminary report summarizes present knowledge concerning the general stratigraphy and structure of the island. Additional surface and underwater geologic studies are needed to further differentiate lithologic units within the complexly faulted Eocene sequence and to obtain additional data concerning the northwestward extension of the general anticlinal structure of the island.