The formation was named for Cedar Mountain in northern Emery County, Utah, where William Lee Stokes first studied the exposures in 1944.

Based on various fossils and radiometric dates, the Cedar Mountain Formation was deposited during the last half of the Early Cretaceous Epoch, about 127 - 98 million years ago (mya).

The Jurassic-Cretaceous boundary in western North America is marked by an unconformity of variable length, and typically signifies 10-49 million years of missing geologic time.

[3] This boundary between the Morrison and Cedar Mountain is commonly marked by a horizon of carbonate nodules[4][5] or by highly polished pebbles that are allegedly gastroliths.

The Naturita is not uniformly distributed and was eroded away in places by the advancing Seaway so that the marine shales of the Mancos Formation lay directly on the Mussentuchit Member or its equivalent.

[6] Only recently did the 125 m (410 ft) thick formation get subdivided into smaller, distinctive beds called members.

The Cedar Mountain Formation is proving to contain one of the world's richest and most diverse Early Cretaceous dinosaur faunas.

The discoveries to date have revealed that the origin of some of the later Cretaceous dinosaurs may lie in Cedar Mountain, but further work is needed to understand the timing and effects the changing position of the North American Plate had on dinosaurian evolution.

The oldest of these assemblages is from the Yellow Cat, Poison Strip and basal Ruby Ranch members.

The small, Ornitholestes-like theropod Nedcolbertia and the brachiosaurid sauropod Cedarosaurus may be considered as relics, with their closest relatives in the Morrison Formation.

In contrast, the polacanthid ankylosaur Gastonia and a yet unnamed iguanodontid are similar to related forms from the Lower Cretaceous of southern England.

Evidence for a middle dinosaur assemblage between the older and younger ones is controversial because the evidence mostly depends on a single specimen of the ornithopod Tenontosaurus from high in the Ruby Ranch Member and the sauropod Astrodon from low in the Ruby Ranch.

[21] Cedrorestes C. crichtoni Eolambia E. caroljonesa Hippodraco H. scutodens A nearly complete, disarticulated skull, cervical, dorsal, sacral, and caudal vertebrae, ribs and haemal arches, partial pectoral and pelvic girdles, and the right arm and leg.

Astrodon Indeterminate Brontomerus B. mcintoshi Cedarosaurus C. weiskopfae Articulated dorsal vertebrae, caudal vertebrae, chevrons, proximal portions of the scapulae, coracoids, sternal plates, right humerus, radius and ulna, metacarpal IV, right pubis, partial pubis, proximal portions of ischia, partial femurs, tibia, metatarsals, phalanx, unguals, ribs, and numerous gastroliths.

[28] Venenosaurus V. dicrocei Disarticulated caudal vertebrae, scapula, radius, ulna, metacarpals, manus phalanges, pubis, ischium, metatarsals, astragalus, chevrons, and ribs.

[29] Indeterminate allosauroid material present in the Lower Yellow Cat and Ruby Ranch Members.

[32] Indeterminate Yurgovuchia Y. doellingi Besides dinosaurs, the Cedar Mountain Formation has produced a wealth of small fossils (a.k.a.

Most of these specimens have been found in the Mussentuchit Member where they are collected by washing the rock through fine window screen.

[7] Ostracods, small crustaceans with clam-like shells, also occur in fresh water deposits, along with "finger-clams" or conchostracans.

Ceratodus C. kempae[35] C. kirklandi C. molossus A new genus and species of orectolobid present in the Mussentuchit Member.

Ameribaatar Ameribaatar zofiae Astroconodon Astroconodon delicatus Bryceomys Bryceomys intermedius Cedaromys Cedaromys bestia Cedaromys parvus Cifelliodon[36] Cifelliodon wahkermoosuch a haramiyidan mammaliaform Corviconodon Corviconodon utahensis Dakotadens[37] Dakotadens pertritus Janumys Janumys erebos Jugulator Jugulator amplissimus Kokopellia Kokopellia juddi Possible metatherian Paracimexomys Paracimexomys perplexus Paracimexomys robisoni Spalacolestes Spalacolestes cretulablatta Spalacolestes inconcinnus Spalacotheridium Spalacotheridium noblei