This data release contains information on gravity cores that were collected by the U.S. Geological Survey in the area of San Pablo Bay and Carquinez Strait, California in 1990, 1991, and 2000. Ten (10) pdf files describe gravity cores that were split, photographed, and imaged by X-rays, and another pdf file contains a core-log legend. In addition, a shapefile provides sample collection data. Seventy-two gravity cores were collected by the U.S. Geological Survey in 1990, 1991, and 2000 from San Pablo Bay and Carquinez Strait, California. Gravity cores from San Pablo Bay contain bioturbated laminated silts and sandy clays, whole and broken bivalve shells (mostly mussels), fossil tube structures, and fine plant or wood fragments. Gravity cores from the channel wall of Carquinez Strait east of San Pablo Bay consist of sand and clay layers, whole and broken bivalve shells (less than in San Pablo Bay), trace fossil tubes, and minute fragments of plant material.