The North Horn Formation is a widespread non-marine sedimentary unit with extensive outcrops exposed in central and eastern Utah.

The formation locally exceeds 3,600 feet (1,100 m) in thickness and is characterized by fluvial, lacustrine, and floodplain dominated systems, representing a terrestrial, high energy, depositional environment.

[10] Laterally, the North Horn Formation nearly spans an 87-mile (140 km) long east–west transect that extends from the Wasatch Plateau on the west and the Book Cliffs, near Green River, on the east, separated in the middle by the San Rafael Swell.

Characteristic dinosaur taxa include the ceratopsian Torosaurus utahensis, the titanosaurid sauropod Alamosaurus sanjuanensis, and the theropod Tyrannosaurus;[11][12][13][14] however, the most frequently occurring taxon in the Cretaceous strata of the North Horn Formation is the Polyglyphanodont squamate Polyglyphanodon.

[6] Fauna recorded from Paleocene strata within the formation appear to be far more diverse and over 70 different taxa have been identified, including frogs, numerous multituberculate, protoeutherians, periptychids, arctocyonids and phenacodontid mammals, crocodyliforms, choristoderes, trace fossils, and palynomorphs.

[16] Bird and dinosaur eggs have also been found at the site, along with unidentified hadrosaur fossils (possibly from Edmontosaurus or Kritosaurus).