The Hanna Formation is a geologic formation in Wyoming. It preserves fossils dating back to the Torrejonian to Tiffanian stages of the Paleogene period.Hanna Formation at Fossilworks.org
See also List of fossiliferous stratigraphic units in Wyoming Paleontology in Wyoming
References
Further reading C. S. Scott and R. C. Fox. 2005. Windows on the evolution of Picrodus (Plesiadapiformes: Primates): morphology and relationships of a species complex from the Paleocene of Alberta. Journal of Paleontology 79(4):635-657 R. Secord. 1998. Paleocene mammalian biostratigraphy of the Carbon Basin, southeastern Wyoming, and age constraints on local phases of tectonism. Rocky Mountain Geology 33(1):119-154 J. A. Lillegraven. 1994. Age of upper reaches of Hanna Formation, northern Hanna Basin, south-central Wyoming. Berliner geowissenschaftliche Abhandlungen E (Paläobiologie) 13:203-219