The Fernando Formation is a Plio-Pleistocene marine mudstone, siltstone and sandstone formation in the greater Los Angeles Basin, Ventura Basin, and Santa Monica Mountains, in Los Angeles County of Southern California. Geology Outcrops of the formation in Santa Monica Mountains National Recreation Area have produced fossil shark teeth. Classification The underlying Repetto Formation is equivalent in age to the Fernando Formation, and some researchers consider it as well as the overlying Pico Formation to be a junior synonym based on benthic foraminifera stages. Other researchers maintain that the Repetto and Pico Formations are distinct stratigraphic units, and that the use of the name "Fernando Formation" should be stopped due to several issues with stratigraphic correlation and access to the type section. See also References Geologic formations of California Fossiliferous stratigraphic units of the United States Paleontology in California Pliocene California Pleistocene California Sandstone formations of the United States Siltstone formations Mudstone formations Geology of Los Angeles County, California Natural history of the Santa Monica Mountains