Snowy Range Formation | |
---|---|
Stratigraphic range: Cambrian | |
Type | Formation |
Location | |
Region | Montana |
Country | United States |
The Snowy Range Formation is a geologic formation in Montana. It preserves fossils dating back to the Cambrian period. It contains characteristic flat pebble conglomerate which sometimes show distinctive red rims [1]
The Cloverly Formation is a geological formation of Early and Late Cretaceous age that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States. It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904. The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains. In 1973, the Cloverly Formation Site was designated as a National Natural Landmark by the National Park Service.
The Eagle Sandstone, originally the Eagle Formation, is a geological formation in Montana whose strata date back to the Late Cretaceous. It is a light to brownish gray to pale yellow-orange, fine-grained sandstone. It contains areas of crossbedding and local shale members. It contains large sandy calcareous concretions. Its thickness varies from 100 to 350 feet due to the lens nature of the individual sandstone layers and local interbedded sandy shale layers.
The Freda Sandstone is a geologic formation in Michigan. It dates back to the Proterozoic. Lithologically, the Freda Sandstone is a lithic, red-brown, cyclic sequence of sandstones, mudstones and shales.
The Deadwood Formation is a geologic formation of the Williston Basin and Western Canada Sedimentary Basin. It is present in parts of North and South Dakota and Montana in the United States, and in parts of Alberta, Saskatchewan, and southwestern corner of Manitoba in Canada. It is of Late Cambrian to Early Ordovician age and was named for exposures in Whitewood Creek near Deadwood, South Dakota. It is a significant aquifer in some areas, and its conglomerates yielded significant quantities of gold in the Black Hills of South Dakota.
The Sappington Formation is a geologic formation in Montana. It preserves fossils dating back to the Carboniferous period.
The Amsden Formation is a geologic formation in Montana. It preserves fossils dating back to the Carboniferous period.
The Jefferson Formation is a geologic formation in Montana. It preserves fossils dating back to the Devonian period.
The Three Forks Shale is a geologic formation in Montana and North Dakota. It preserves fossils dating back to the Devonian period.
The Melville Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period.
The Polecat Bench Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period. The polyglyphanodontian lizard Chamops is known from this formation.
The Renova Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period.
The Tullock Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period.
The Park City Formation is a geologic formation in Montana and Utah. It preserves fossils dating back to the Permian period.
The Dinwoody Formation is a geologic formation in Montana. It preserves fossils dating back to the Triassic period.
The Thaynes Formation is a geologic formation in Montana and Idaho, United States. It preserves fossils dating back to the Triassic period, such as Ammonoidea, Actinopterygii, Actinistia, Conodonta, Gastropoda, Nautiloidea, Ichthyosauria, and others. A diverse fauna known as the Paris Biota has been described from the Thaynes Formation.
The Belle Fourche Formation or Belle Fourche Shale is a fossiliferous early Late-Cretaceous geologic formation classification in Wyoming. Named for outcrops in Belle Fourche River, Wyoming, this unit name is also used in Montana, North Dakota, and South Dakota.
The Troublesome Formation is a geologic formation in Colorado. It preserves fossils dating back to the Neogene period. It consists of Pale shades of pink, tan, gray, green, and white interbedded siltstone and mudstone, less abundant arkosic sandstone and conglomerate, and sparse limestone and altered crystal-vitric ash and tuff; generally poorly consolidated. It includes atypical deposits containing abundant pink, granitic cobbles and boulders along the western parts of the outcrop in the west-central and southwestern parts of the Granby Quadrangle, Fossil mammals from three sites indicate a late Oligocene age.
The Briones Formation is a Late/Upper Miocene epoch geologic formation of the East Bay region in the San Francisco Bay Area, California.
The Conglomerado Cualac is a geologic formation in Mexico. First described by Guzmán in 1959, under the name Cuarcita Cualac. Later, Erben (1956) gave it their actual name. It consist of thick beds of a hard, white and sometimes yellowish conglomerate with a cuarcitic matrix. This conglomerate compounds almost exclusively of milky quartz pebbles between .5 and 5 centimeters of diameter. It also presents, in less quantity, pebbles of schist, gneiss, and tuff. Its thickness varies between 30 and more than 200 meters. It preserves fossils dating back to the Jurassic period.
The Copper Harbor Conglomerate is a geologic formation in Michigan. It is part of the larger Oronto Group and its formation dates to the Stenian period of the Proterozoic.