The Latham Shale 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 U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. It contains some of the most important examples of

Lower Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovici ...

trilobites in the world. Fossils of 12 different species of

trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...

and 9 other Cambrian invertebrates, including articulate brachiopods and

Anomalocaris ''Anomalocaris'' (from Ancient Greek , meaning "unlike", and , meaning "shrimp", with the intended meaning "unlike other shrimp") is an extinct genus of radiodont, an order of early-diverging stem-group marine arthropods. It is best known fro ...

appendages, have been found in the formation. Fossil veins are so thick that in certain places nearly every rock contains trilobite fossils, making it a destination for trilobite collectors worldwide.

Oncolite Oncolites are sedimentary structures composed of oncoids, which are layered structures formed by the growth of one or more species of microorganisms, usually containing cyanobacteria. Oncolites are very similar to stromatolites, but, instead of ...

fossils are also found in significant quantities. Due to the fragmentary nature of most trilobites found in the formation, it may represent a trilobite molting ground or just an area where ocean currents brought dead trilobite exoskeletons. Latham shale is the primary rock formation in the southern Marble Mountains of the

Mojave Desert The Mojave Desert (; ; ) is a desert in the rain shadow of the southern Sierra Nevada mountains and Transverse Ranges in the Southwestern United States. Named for the Indigenous peoples of the Americas, indigenous Mohave people, it is located pr ...

where it is found in deposits thick.

References

Cambrian California Shale formations of the United States {{Cambrian-stub

See also

References