The San Joaquin Formation is a Pliocene epoch geologic formation in the lower half of the San Joaquin Valley in central California.USGS.gov: "Neogene Gas Total Petroleum System—Neogene Nonassociated Gas Assessment Unit of the San Joaquin Basin Province"; Chapter 22 of the Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California; by Allegra Hosford Scheirer and Leslie B. Magoon.
Geology With the underlying Etchegoin Formation, it is associated with the numerous oil fields in the central and southern San Joaquin Valley. It is overlain by the Tulare Formation.
It preserves fossils dating back to the Neogene period of the Cenozoic Era.
See also
List of fossiliferous stratigraphic units in California Paleontology in California
References
Bartow, J.A., 1991, The Cenozoic evolution of the San Joaquin Valley, California: U.S. Geological Survey Professional Paper 1501, 40 p. Goudkoff, P.P., 1943, Correlation of oil field formations on west side of San Joaquin Valley, in Jenkins, O.P., ed., Geologic formations and economic development of the oil and gas fields of California: San Francisco, Calif., State of California, Department of Natural Resources, Division of Mines Bulletin No. 118, p. 247-252.