The Santa Cruz Mudstone is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. The

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

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 Monterey Formation is an extensive Miocene oil-rich geological sedimentary formation in California, with outcrops of the formation in parts of the California Coast Ranges, Peninsular Ranges, and on some of California's off-shore islan ...

. The formation preserves bivalve and

echinoid Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

fossils as well as vertebrates of '' Parabalaenoptera baulinensis'' and ''

Otodus megalodon Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. It was formerly thought to be a member ...

''. The formation dates back to the Late Miocene (

Tortonian The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Torto ...

to Messinian)

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

.Balinas Point
at Fossilworks.orgBolinas Bay
at Fossilworks.orgWaddell Creek
at Fossilworks.org

References

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* 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 Geologic formations of California Neogene California Messinian Tortonian Mudstone formations Deep marine deposits Fluvial deposits Paleontology in California

See also

References

Further reading