Paleogene United States

Coryphodon (from Greek , "point", and , "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of pantodonts of the family Coryphodontidae.

mountain-building episode in Western North America, 80-35 million years ago

Orohippus (from the Greek , 'mountain' and , 'horse') is an extinct equid that lived in the Eocene (about 50 million years ago). Its fossils have been unearthed in Oregon, Colorado, Utah, and Wyoming.

Epihippus is an extinct genus of the modern horse family Equidae that lived in the Eocene, from 46 to 38 million years ago.

Cimolestes (from Ancient Greek , 'chalk robber') is a genus of early eutherians with a full complement of teeth adapted for eating insects and other small animals. Paleontologists have disagreed on its relationship to other mammals, in part because quite different animals were assigned to the genus, making Cimolestes a grade taxon of animals with similar features rather than a genus of closely related ones. Fossils have been found in North America, South America, Europe and Africa. Cimolestes first appeared during the Late Cretaceous of North America. According to some paleontologists, Cimoles

Cynthiacetus is an extinct genus of basilosaurid early whale that lived during the Late Eocene (Bartonian-Priabonian, .) Specimens have been found in the southeastern United States and Peru (Otuma Formation).

extinct shark species

alt=Coniophis sp. snake vertebra|thumb|Coniophis sp. vertebra 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, such as lizards and salamanders. 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

species of fossil shark

Periptychus is an extinct genus of mammal belonging to the family Periptychidae. It lived from the Early to Late Paleocene and its fossil remains have been found in North America.

Leptomeryx is an extinct genus of artiodactyl that lived in North America during the middle Eocene through early Miocene. One of the earliest ruminants, it belongs to the extinct family Leptomerycidae, which is related to today's chevrotains. Most fossils were found in the badlands of the Midwestern United States in sedimentary rocks of the White River Group, in the Brule and Chadron formations. Additional remains have been reported from southern Canada and Mexico. The genus was scientifically described in 1853 by Joseph Leidy and includes several species.

continental flood basalt province in the Western United States