Santa Cruz Mudstone

Santa Cruz Mudstone
Stratigraphic range: Tortonian-Messinian
Type	Formation
Underlies	Purisima Formation
Overlies	Santa Margarita Sandstone
Thickness	>2,700 m (8,900 ft)
Lithology
Primary	Siliceous organic mudstone
Location
Coordinates	37.1°N 122.3°W / 37.1; -122.3
Approximate paleocoordinates	36.6°N 119.8°W / 36.6; -119.8
Region	California
Country	United States
Extent	Santa Cruz Mountains
Type section
Named for	Santa Cruz County
Santa Cruz Mudstone (California)

The Santa Cruz Mudstone is a geologic formation in California. The siliceous organic mudstones of the formation were deposited in deep water and fluvial environments. The formation overlies the Santa Margarita Sandstone and is overlain by the Purisima Formation. The Santa Cruz Mudstone was formerly considered part of the Monterey Formation. The formation preserves bivalve and echinoid fossils as well as vertebrates of Parabalaenoptera baulinensis and Otodus megalodon. The formation dates back to the Late Miocene (Tortonian to Messinian) period.

See also

• List of fossiliferous stratigraphic units in California
• Paleontology in California

Further reading

• J. C. Clark. 1981. Stratigraphy, paleontology, and geology of the Central Santa Cruz Mountains, California Coast Ranges. United States Geological Survey Professional Paper 1168:1-51
• D. S. Jordan and H. Hanibal. 1923. Fossil sharks and rays of the Pacific slope of North America. Bulletin of the Southern California Academy of Sciences 22:27-63
• C. V. Zeigler, G. L. Chan, and L. G. Barnes. 1997. A new late Miocene balaenopterid whale (Cetacea: Mysticeti), Parabalaenoptera baulinensis, (new genus and species) from the Santa Cruz Mudstone, Point Reyes Peninsula, California. Proceedings of the California Academy of Sciences 50(4):115-138