The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in the dry season. Each pair of layers is called a varve and represents one year. The sediments of the Green River Formation present a continuous record of six million years. The mean thickness of a varve here is 0.18 mm, with a minimum thickness of 0.014 mm and maximum of 9.8 mm.
Fossil Butte National Monument is a United States National Monument managed by the National Park Service, located 15 miles (24 km) west of Kemmerer, Wyoming, United States. It centers on an assemblage of Eocene Epoch animal and plant fossils associated with Fossil Lake—the smallest lake of the three great lakes which were then present in what are now Wyoming, Utah, and Colorado. The other two lakes were Lake Gosiute and Lake Uinta. Fossil Butte National Monument was established as a national monument on October 23, 1972.
Heliobatis is an extinct genus of stingray in the Myliobatiformes family Dasyatidae. At present the genus contains the single species Heliobatis radians.
The Laramie Formation is a geologic formation of the Late Cretaceous (Maastrichtian) age, named by Clarence King in 1876 for exposures in northeastern Colorado, in the United States. It was deposited on a coastal plain and in coastal swamps that flanked the Western Interior Seaway. It contains coal, clay and uranium deposits, as well as plant and animal fossils, including dinosaur remains. The formation contains some of the oldest records of Grass in western North America.
Priscacara, is a genus of extinct temperate bass described from Early to Middle Eocene fossils. It is characterized by a sunfish-like body and its stout dorsal and anal spines. The genus is best known from the Green River Formation of Wyoming, Utah and Colorado. Mass deaths of Priscacara suggest it formed schools.
Paleoamphiuma is an extinct genus of prehistoric salamanders known from the Green River Formation in Wyoming, the United States. It was initially classified within the family Amphiumidae, but Gardner (2003) suggested that it be better placed within the family Sirenidae. The single known specimen measures 39 cm in length. It was named in reference to the extant salamander Amphiuma.
The White River Fauna are fossil animals found in the White River Group of South Dakota, North Dakota, Wyoming, Colorado and Nebraska in the United States. In southwest South Dakota and northwest Nebraska, these fossils are characteristic of the White River Badlands, though they can be found far beyond the limits of the White River watershed.
Asterotrygon is an extinct genus of stingray from the Eocene Green River Formation in Wyoming. Several complete skeletons representing juveniles, adults, males and females have been uncovered from the late early Eocene Fossil Butte Member of the formation. The type and only species, A. maloneyi, was named in 2004 on the basis of these fossils. Another stingray, Heliobatis, is also known from the formation. Asterotrygon is a primitive stingray closely related to the living family Urolophidae whose ancestors likely originated in the Indo-Pacific. It lived in Fossil Lake, a body of water that existed in a subtropical mountainous region for only about 2 million years.
Saniwa is an extinct genus of varanid lizard that lived during the Eocene epoch. It is known from well-preserved fossils found in the Bridger and Green River Formations of Wyoming, United States. The type species S. ensidens was described in 1870 as the first fossil lizard known from North America. A second species, S.orsmaelensis, is recognised from remains found in Europe. It is a close relative of Varanus, the genus that includes monitor lizards.
Bahndwivici is an extinct genus of lizard known from a nearly complete and articulated skeleton discovered in rocks of the Green River Formation of Wyoming, United States. The skeleton is very similar to that of the modern Chinese crocodile lizard, Shinisaurus.
Paleontology in Wyoming includes research into the prehistoric life of the U.S. state of Wyoming as well as investigations conducted by Wyomingite researchers and institutions into ancient life occurring elsewhere.
The Polychrotidae family of iguanian lizards contains the living genus Polychrus and the extinct genus Afairiguana. The family Polychrotidae was once thought to encompass all anoles, including those in the genus Anolis. Studies of the evolutionary relationships of anoles based on molecular information has shown that Polychrus is not closely related to Anolis, but instead closer to Hoplocercidae. It is therefore not part of Dactyloidae and instead is treated as the family, Polychrotidae.
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 Bridger Formation is a geologic formation in southwestern Wyoming. It preserves fossils dating back to the Bridgerian and Uintan stages of the Paleogene Period. The formation was named by American geologist Ferdinand Vandeveer Hayden for Fort Bridger, which had itself been named for mountain man Jim Bridger. The Bridger Wilderness covers much of the Bridger Formation's area.
Magnuviator is a genus of extinct iguanomorph lizard from the Late Cretaceous of Montana, US. It contains one species, M. ovimonsensis, described in 2017 by DeMar et al. from two specimens that were discovered in the Egg Mountain nesting site. Magnuviator is closest related to the Asian Saichangurvel and Temujinia, which form the group Temujiniidae. Unlike other members of the Iguanomorpha, however, Magnuviator bears a distinct articulating notch on its tibia for the ankle bones, which has traditionally been considered a characteristic of non-iguanomorph lizards. The morphology of its teeth suggests that its diet would have mainly consisted of wasps, like the modern phyrnosomatid iguanians Callisaurus and Urosaurus, although it also shows some adaptations to herbivory.
Coniophis is an extinct genus of snakes from the late Cretaceous period. The type species, Coniophis precedes, was about 7 cm long and had snake-like teeth and body form, with a skull and a largely lizard-like bone structure. It probably ate small vertebrates. The fossil remains of Coniophis were first discovered at the end of the 19th century in the Lance Formation of the US state of Wyoming, and were described in 1892 by Othniel Charles Marsh. For the genus Coniophis, a number of other species have been described. Their affiliation is, however, poorly secured, mostly based on vertebrae descriptions from only a few fossils.
The geology of Wyoming includes some of the oldest Archean rocks in North America, overlain by thick marine and terrestrial sediments formed during the Paleozoic, Mesozoic and Cenozoic, including oil, gas and coal deposits. Throughout its geologic history, Wyoming has been uplifted several times during the formation of the Rocky Mountains, which produced complicated faulting that traps hydrocarbons.
Cyrilavis is an extinct genus of halcyornithid bird from the Early Eocene Fossil Butte Member of the Green River Formation, United States. The genus contains two species, Cyrilavis olsoni and Cyrilavis colburnorum.
Paakniwatavis is a genus of extinct waterfowl from the early Eocene Green River Formation of Wyoming, United States. The genus contains a single species, P. grandei, known from a partial skeleton with a skull.
The Green River Formation is a geological formation located in the Intermountain West of the United States, in the states of Colorado, Utah, and Wyoming. It comprises sediments deposited during the Early Eocene in a series of large freshwater lakes: Lake Gosiute, Lake Uinta, and Fossil Lake. It preserves a high diversity of freshwater fish, birds, reptiles, and mammals, with some sections of the formation qualifying as Konservat-Lagerstätten due to their extremely well-preserved fossils.
