The Arikaree River is a 156-mile-long (251 km) river in the central Great Plains of North America. It lies mostly in the American state of Colorado, draining land between the North and South Forks of the Republican River, and it flows into the North Fork in Nebraska after flowing a short distance through Kansas. It is a designated area within the Colorado Natural Areas Program to protect native and uncommon species that may be endangered or threatened.
The North Fork Republican River is a 55.4-mile-long (89.2 km) tributary of the Republican River. It flows eastward from a source in Yuma County, Colorado to just north of Haigler in Dundy County, Nebraska. There it joins with the Arikaree River to form the Republican River.
The White River Fauna are fossil animals found in the White River Badlands of South Dakota, Wyoming, Colorado and Nebraska in the United States including Badlands National Park.
The Fox Hills Formation is a Cretaceous geologic formation in the northwestern Great Plains of North America. It is present from Alberta on the north to Colorado in the south.
The Mowry Shale is an Early Cretaceous geologic formation. The formation was named for Mowrie Creek, northwest of Buffalo in Johnson County, Wyoming.
The Kiowa Formation or Kiowa Shale is a Cretaceous geologic formation in Kansas, diminishing to member status in Colorado and Oklahoma. In Colorado, the Kiowa Shale was classified as a member of the now abandoned Purgatoire Formation. In the vicinity of Longford, Kansas, the local Longford member comprises thinly bedded siltstone, clay, polished gravel, lignite, and sandstone suggests a river and estuary environment.
The Mancos Shale or Mancos Group is a Late Cretaceous geologic formation of the Western United States.
Ashworth Glacier is an Antarctic glacier with sharply delineated sides, flowing west from Supporters Range into Mill Glacier, 5 kilometres (3 mi) north of Mount Iveagh. It was named by the Advisory Committee on Antarctic Names in 2007, after Allan C. Ashworth, Professor of Paleontology and Stratigraphy at North Dakota State University. He discovered the only yet known fly and beetle fossils in Antarctica in the nearby Dominion Range.
The Brule Formation was deposited between 33 and 30 million years ago, roughly the Rupelian age (Oligocene). It occurs as a subunit of the White River Formation in Nebraska, Colorado, North Dakota, South Dakota, and Wyoming.
The Bullion Creek Formation is a geologic formation in western North Dakota. It preserves bones and tracks of an extinct crocodile and other fossils of Late Paleocene age.
The Cannonball Formation is a geologic formation in western North Dakota. It preserves fossils dating back to the Paleogene Period.
The Ludlow Formation is a geologic formation in western North Dakota. It preserves fossils dating back to the Paleogene Period.
The Tongue River Member is the uppermost geologic member of the Fort Union Formation in Montana, North Dakota, Wyoming. The strata are yellow or light-colored massive sandstones and numerous thick coal beds.
The Inyan Kara Group is a geologic group classification applied in South Dakota and adopted in portions of Wyoming and Montana. It preserves fossils of the mid-Cretaceous period. Of late Albian age, this classification correlates with the lower Dakota Formation known in the southwest corner of the State.
The Rosebud Formation is a geologic formation of cemented pink silt in Nebraska and South Dakota, dating to the early middle Miocene epoch of the Neogene period. Possibly named for its color, no type location has been set for this unit, but it is associated with the Valentine Formation along the Niobrara River. The fine silt of the formation forms an aquitard beneath the Ogallala Aquifer carried by the Valentine Formation. Many springs from the Valentine sands flow down the Rosebud outcrop into the Niobrara River.
The Turtle Butte Formation is a geologic formation at Turtle Butte in South Dakota. It preserves fossils dating back to the Paleogene period.
The Fort Randall Formation is a geologic formation in South Dakota, United States. It preserves fossils dating back to the Neogene period.
The Cheyenne Sandstone is an Early Cretaceous geologic formation in Kansas.
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 Purgatoire Formation is an abandoned (1987) Cretaceous period geologic formation classification. The classification was used in Colorado, New Mexico, and Oklahoma, with mentions in older geologic literature in neighboring states.
