The Wilcox Group is an important geologic group in the Gulf of Mexico Basin and surrounding onshore areas from Mexico and Texas to Louisiana and Alabama. The group ranges in age from Paleocene to Eocene and is in Texas subdivided into the Calvert Bluff, Simsboro and Hooper Formations, and in Alabama into the Nanafalia and Hatchetigbee Formations. Other subdivisions are the Lower, Middle and Upper Wilcox Subgroups, and the Carrizo and Indio Formations.
The Black Creek Group is a Late Cretaceous -aged geologic group in the southeastern United States, where it is known from the coastal plain of North Carolina and South Carolina. Deposited in brackish or nearshore marine conditions, it preserves fossils, including a diversity of dinosaurs and marine reptiles.
The Choptank Formation is a geologic formation in Virginia and Maryland. It preserves fossils dating from the Miocene epoch of the Neogene period.
The Williamsburg Formation is a geologic formation in South Carolina consisting of sandy shale and clayey sand. It is a member of the Black Mingo Group and overlays the Rhems Formation. It preserves fossils, among others coprolites, dating back to the Paleogene period.
The Hatchetigbee Bluff Formation is a geologic formation in Alabama, Georgia, Louisiana and Mississippi. The youngest unit of the Wilcox Group preserves fossils dating back to the Ypresian stage of the Eocene period, or Wasatchian in the NALMA classification. The formation is named for Hatchetigbee Bluff on the Tombigbee River, Washington County, Alabama.
The Alachua Formation is a Miocene geologic formation in Florida. The claystones, sandstones and phosphorites of the formation preserve many fossils of mammals, birds, reptiles and fish, among others megalodon.
Yazoo Clay is a clay geologic formation in Alabama, Louisiana, and Mississippi. It was named after a bluff along the Yazoo River at Yazoo City, Mississippi. It contains is a type of clay known as montmorillonite, making it a poor foundation material due to the fact that moisture causes extreme changes in volume. Sand, pyrite, and marl have all been noted in the formation. It preserves fossils from the Eocene, including the prehistoric cetaceans Basilosaurus and Zygorhiza, and the marine snake Pterosphenus. Sharks, rays, eels, and fish have also been found from the formation.
The Wasatch Formation (Tw) is an extensive highly fossiliferous geologic formation stretching across several basins in Idaho, Montana, Wyoming, Utah and western Colorado. It preserves fossils dating back to the Early Eocene period. The formation defines the Wasatchian or Lostcabinian, a period of time used within the NALMA classification, but the formation ranges in age from the Clarkforkian to Bridgerian.
The Indian Meadows Formation is a Wasatchian geologic formation in Wyoming. It preserves fossils dating back to the Ypresian stage of the Eocene period.
The Chalk Butte Formation is a geologic formation in Oregon, which forms a part of the Idaho Group. It preserves fossils dating back to the Neogene period. It was proposed along with the Grassy Mountain Basalt Formation and the Kern Basin Formation as a division of the Idaho Group rocks in the Mitchell Butte Quadrangle. The predominant rock types are tuffaceous sandstones, siltstones, and conglomerates with smaller amounts of tuff, ash beds, and freshwater limestone. A partial section at the type location determined the formation to be about 538 feet thick.
The Punchbowl Formation is a sedimentary sandstone geologic formation in the northern San Gabriel Mountains, above the Antelope Valley in Los Angeles County, southern California.
The San Antonio Formation is a middle to late Pleistocene geologic formation in California. It preserves fossils.
The Margaret Formation is a geologic formation of the Eureka Sound Group in the Sverdrup Basin in Northwest Territories and Nunavut, Canada. The unit belonging to the Eureka Sound Group which crops out at Ellesmere Island preserves fossils dating back to the Early Eocene period, or Wasatchian in the NALMA classification.
The Cuscatlán Formation is a geologic formation in El Salvador. It preserves fossils dating back to the Pliocene to Middle Pleistocene period.
The Gracias Formation is a geologic formation in Honduras. The mainly sandstones, siltstones and claystones preserve vertebrate fossils dating back to the Neogene period.
The Sundvollen Formation is a geologic formation cropping out along the northern and eastern shores of Steinsfjorden, Oslo Region, Norway. It preserves fossils dating back to the Gorstian to Ludfordian stages of the Late Silurian period.
The Moskvoretskaya Formation is a Middle Jurassic geologic formation in the European part of Russia. It consists of continental claystones, siltstones and sandstones deposited in karstified segments of underlying Middle Carboniferous limestone, that would have formed underground aquifers.
The Onzole Formation is an Early Pliocene geologic formation in the Borbón Basin of northwestern Ecuador. The formation consists of a shallow marine sandstone member containing many fish fossils, among which megalodon, and a deep water member comprising tuffaceous shales and mudstones containing gastropods, bivalves and scaphopods.
The Calvert Formation is a geologic formation in Maryland, Virginia, and Delaware. It preserves fossils dating back to the early to middle Miocene epoch of the Neogene period. It is one of the three formations which make up the Calvert Cliffs, all of which are part of the Chesapeake Group.
The Silveirinha Formation is an Early Eocene geologic formation of the Mondego Basin in the Região Centro of central-western Portugal. The sandstones, siltstones and conglomerates were deposited in an alluvial environment.
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