Crowder Formation

The Crowder Formation is a geologic formation in the Central and Western Mojave Desert, in northern Los Angeles County and eastern San Bernardino County, in Southern California.^[2]

Areas where it is exposed include at the bases of the northern San Gabriel Mountains and northwestern San Bernardino Mountains, and in the Cajon Pass between them.^[2][3][4]

The Crowder Formation was formed during the Pliocene epoch of the Neogene period.^[2][3] The formation was deposited by drainages carrying distinctive volcanic and metamorphic clasts from the Victorville area southward.^[4]

It overlies the crystalline San Gabriel Basement Complex in its eastern section, and the San Francisquito Formation in its western section in the Antelope Valley/San Gabriels.^{[citation needed]}

The formation preserves fossils of insects, reptiles, rodents, birds, and larger mammals. The species date back to the Miocene and Pliocene epochs of the Neogene period.^[5] 29 taxa were collected by the San Bernardino County Museum from the Cajon Pass area of the Crowder Formation.^[3]

• Neogene geologic formations in California
• List of fossiliferous stratigraphic units in California
• Paleontology in California

• "The Physical and Magnetic Stratigraphy of the Miocene Crowder Formation, Cajon Pass, Southern California"; by Douglas Scott Winston, University of Southern California; Los Angeles, 1985.

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