Wasatch fauna consists of many groups of mammals, including numerous genera of primates, artiodactyls, perissodactyls, rodents, carnivora, insectivora, hyaenodonta and others.

The formation, first named as Wasatch Group in 1873 by Ferdinand Vandeveer Hayden, was deposited in alluvial, fluvial and lacustrine environments and comprises sandstones, siltstones, mudstones and shales with coal or lignite beds representing wet floodplain settings.

Overlying them and extending to the top of the butte are the much steeper buff-to-white beds of the Green River Formation, which are about 300 feet (91 m) thick.

[14] There is a regional, angular unconformity between the Fort Union and Wasatch Formations in the northern portion of the Powder River Basin.

[15] Many local subdivisions of the formation exist, the following members have been named in the literature:[13] In the Fossil Basin at the Fossil Butte National Monument, Wyoming, the Wasatch Formation consists primarily of brightly variegated mudstones with subordinate interbedded siltstones, sandstones, and conglomerates and represents deposition on an intermontane alluvial plain.

These members consist of infrequent lenses of fluvial-channel sandstones interbedded within thick units of variegated red, orange, purple and gray overbank and paleosol mudstones.

[17] The Molina Member represents a sudden change in the tectonic and/or climatic regimes, that caused an influx of laterally-continuous, fine, coarse and locally conglomeratic sands into the basin.

These sandy strata of the Molina Member form continuous, erosion-resistant benches that extend to the north of the type section for approximately 25 kilometres (16 mi).

[25] Cobbles and pebbles in the Wasatch are rich in feldspathic rock fragments, with individual samples containing as much as 40 percent,[26] derived from erosion of the Precambrian core of the Bighorn Mountains.

[18] The presence of the Kingsbury Conglomerate at the base of the Wasatch Formation indicates that tectonic activity in the immediate vicinity of the Powder River Basin was intensifying.

The Wasatchian followed the Clarkforkian stage (56.8-55.8 Ma) and is defined by the simultaneous first appearance of adapid and omomyid euprimates, hyaenodontid creodonts, perissodactyls and artiodactyls.

[33] At the Fossil Butte National Monument, the Wasatch Formation preserved ichnofossils attributed to arthropods and described as Lunulichnus tuberosus.

Flood basin deposits (dominated by alluvial paleosols with pronounced color variegation) are characterized by common Planolites, rare Skolithos and small, meniscate plug-shaped burrows, possibly Celliforma.

[35] Crevasse splay deposits (current-rippled to planar laminated, fine-grained sandstone to siltstone) are characterized by a mixed assemblage of vertical (Arenicolites, Skolithos, unwalled sinuous shafts, shafts with discoidal lenses of sediment), sub-vertical (Camborygma and Thalassinoides) and horizontal (Scoyenia, Rusophycus, Taenidium, Planolites and Palaeophycus) burrows.

[120] The Wasatch Formation is a tight gas reservoir rock in the Greater Natural Buttes Field in the Uinta Basin of Utah and Colorado.