From Introduction: "This bulletin is the second report so far published and deals primarily with the large oil fields of the San Joaquin Valley of California. The work will be continued as rapidly as possible, and will include all of the more important petroleum districts of the United States. The prime object of the investigations was to determine the economic value of the petroleums and natural gases in the United States with especial reference to the supplies in the public lands, and to ascertain how these resources could be utilized in the industries with least waste and greatest efficiency. "