Colorado, The Cloverly Formation is a geological formation of Early and Late Cretaceous age (Valanginian to Cenomanian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States.

It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904.

[1][2] The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains.

The individual ages of the members are listed below:[6] The sediments of the Cloverly Formation were deposited in alluvial and floodplain environments.

[2][4][7] Animals recovered include the dinosaurs Deinonychus, Microvenator, Tenontosaurus, Zephyrosaurus and Sauropelta as well as fragmentary remains of Titanosaurs, Ankylosaurs and Ornithomimids.

[11] Articulated skeletons are often encased in carbonate caliche deposits that require acid to be removed safely.

[10] Juvenile remains are sometimes found together, suggesting that young Tenontosaurus lived in sibling groups.

Remains identified by John Ostrom as Ornithomimus are suspected by Jack Horner to be of a new ornithomimid genus.

[10] Possible remains of a microraptorian, a troodontid, and a basal tyrannosauroid similar to Moros have also been found here as well.

"[10] Tenontosaurus remains have been recovered in association with Deinonychus teeth, suggesting a predator-prey relationship between the two.

[20] The type specimen AMNH 3041[10] was recovered by Barnum Brown from Cloverly strata in Montana in 1933.