The Bull Fork Formation is a geologic formation in north central Kentucky and southwestern Ohio. It preserves fossils dating back to the Ordovician period.
The Oranda Formation is a geologic formation in Virginia. It preserves fossils dating back to the Ordovician period.
The Bowen Formation is an Ordovician-age geological formation in the Appalachian region of the eastern United States. It occupies a thin stratigraphic range between the Wardell and Witten formations in some areas of southwest Virginia and northeast Tennessee. It is particularly well-exposed in Tazewell County, Virginia. Unlike its encompassing strata, the Bowen Formation is mostly calcareous sandstone and mudrock rather than limestone. The thicker upper part of the formation is composed of layered red mudrock which is replete with mudcracks. The thinner lower part, which is not always preserved, is a coarser unit of dark grey stratified sandstone which weathers to a rusty-brown color. Fossils are rare, restricted to stromatolites and Tetradium fibratum.
The Fernvale Limestone is a geologic formation in Alabama, Arkansas, Illinois, Missouri, Oklahoma, and Tennessee. It preserves fossils dating back to the Ordovician period.
The Ely Springs Dolomite is an Ordovician period geologic formation in the Southwestern United States.
The Harkless Formation is a geologic formation in Nevada and California. It preserves fossils dating back to the Cambrian period.
The Stirling Quartzite Formation is a geologic formation in the northern Mojave Desert of Inyo County, California and Nye County and Clark County, Nevada.
The Wood Canyon Formation is a geologic formation in the northern Mojave Desert of Inyo County, California and Nye County and Clark County, Nevada.
The Al Rose Formation is a geologic formation in California. It consists mostly of siltstone, mudstone and shale, with some chert and occasional limestone. In it are found graptolite and trilobite fossils dating back to the Ordovician period.
The Antelope Valley Limestone is a limestone geologic formation of the Pogonip Group in southern Nevada.
The Badger Flat Limestone is a limestone geologic formation in California.
The Zabriskie Quartzite is a Cambrian Period geologic formation of the northern Mojave Desert, in Inyo County, California and Nye County, Nevada.
The Chatsworth Formation is a Cretaceous period sandstone geologic formation in the Simi Hills and western Santa Susana Mountains of southern California.
The Mt. Eden Formation is a geologic formation in Riverside County, California. It underlies the San Timoteo Formation, and preserves fossils dating back to the Neogene period.
The Etchegoin Formation is a Pliocene epoch geologic formation in the lower half of the San Joaquin Valley in central California.
The Coso Formation is a geologic formation in the Coso Range of the Mojave Desert, in Inyo County, California.
The Chanac Formation is a Cenozoic Era sandstone geologic formation in the southeastern San Joaquin Valley, within Kern County, California.
The Payton Ranch Limestone is a geologic formation in the Klamath Mountains province (geology) of Northwestern California.
The Cobourg Formation is a geologic formation in Ontario. It preserves fossils dating back to the Ordovician period. Technically the formation extends into New York State with Canadian section called Lindsay Formation. The formation was named by Raymond (1921). The Cobourg formation was estimated to have a total thickness of about 70 m.
The Becscie Formation is a geologic formation in Quebec. It preserves fossils dating back to the early Silurian period.
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