Tongue River Member

Tongue River Member
Stratigraphic range: Paleogene
Mining the coal-rich Tongue River Member, Fort Union Formation (Wyodak coal mine, Powder River Basin, Wyoming)
Type	Member
Unit of	Fort Union Formation
Overlies	Lebo Member
Location
Region	North Dakota, Wyoming
Country	United States

The Tongue River Member is the uppermost geologic member of the Fort Union Formation in Montana, North Dakota, Wyoming.^[1] The strata are yellow or light-colored massive sandstones and numerous thick coal beds.^[2]

The vertebrate fossil fauna includes fishes, turtles, crocodiles, and mammals. Mammalian genera known from rocks of both the Torrejonian and the Tiffanian land mammal ages (middle and late Paleocene) are present.^[3]

See also

• List of fossiliferous stratigraphic units in North Dakota
• Paleontology in North Dakota
• Paleontology in Wyoming

References

1. N. M. Denson; J. H. Dover; L. M. Osmonson (1978). "Lower Tertiary coal bed distribution and coal resources of the Reno Junction-Antelope Creek area, Campbell, Converse, Niobrara, and Weston counties, Wyoming". Miscellaneous Field Studies Map. 960. doi:10.3133/MF960. Wikidata Q62118849.
2. Thom, W.T., Jr., and Dobbin, C.E., 1924, Stratigraphy of Cretaceous-Eocene transition beds in eastern Montana and the Dakotas: Geological Society of America Bulletin, v. 35, no. 9, p. 481-505.
3. Various Contributors to the Paleobiology Database. "Fossilworks: Gateway to the Paleobiology Database". Retrieved 17 December 2021.

Sandstone and mudstone of the Tongue River Member, Fort Union Formation.

Mudstones and sandstone, Tongue River Member, exposed in a roadcut, US Highway 87