Tatman Formation
Stratigraphic range: Ypresian (Lostcabinian) ~55.8–50 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Lithology
Primary	Shale
Location
Coordinates	44°12′N 108°36′W / 44.2°N 108.6°W / 44.2; -108.6
Approximate paleocoordinates	49°00′N 91°30′W / 49.0°N 91.5°W / 49.0; -91.5
Region	Wyoming
Country	United States
Extent	Bighorn Basin
Tatman Formation (the United States) Show map of the United States Tatman Formation (Wyoming) Show map of Wyoming

The Tatman Formation is a Wasatchian geologic formation in Wyoming. It preserves fossils dating back to the Ypresian stage of the Eocene period.^[1]

Fossil content

The following fossils have been recovered from the formation:^[1][2]

Flora

Wasatchian correlations

Wasatchian correlations in North America

Formation	Wasatch	DeBeque	Claron	Indian Meadows	Pass Peak	Tatman	Willwood	Golden Valley	Coldwater	Allenby	Kamloops	Ootsa Lake	Margaret	Nanjemoy	Hatchetigbee	Tetas de Cabra	Hannold Hill	Coalmont	Cuchara	Galisteo	San Jose	Ypresian (IUCS) • Itaboraian (SALMA) Bumbanian (ALMA) • Mangaorapan (NZ)
Basin	Powder River Uinta Piceance Colorado Plateau Wind River Green River Bighorn	Piceance	Colorado Plateau	Wind River	Green River	Bighorn		Williston	Okanagan	Princeton	Buck Creek	Nechako	Sverdrup	Potomac	GoM	Laguna Salada	Rio Grande	North Park	Raton	Galisteo	San Juan	Tatman Formation (North America)
Country	United States								Canada					United States		Mexico	United States
Copelemur
Coryphodon
Diacodexis
Homogalax
Oxyaena
Paramys
Primates
Birds
Reptiles
Fish
Insects
Flora
Environments	Alluvial-fluvio-lacustrine	Fluvial				Fluvial	Fluvio-lacustrine	Fluvial	Lacustrine		Fluvio-lacustrine		Deltaic-paludal	Shallow marine		Fluvial	Shallow marine	Fluvial		Fluvial		Wasatchian volcanoclastics Wasatchian fauna Wasatchian flora
Volcanic	Yes	No							Yes	No	Yes	No	Yes	No						Yes	No