Tongue River Formation (SDTtr;0)

White, gray, and tan, massive, cross-bedded sandstone with interbedded gray, brown, and green claystone, bentonitic claystone, clayely siltstone, carbonate concretions, and lignite. Thickness up to 285 ft (87 m).

State	South Dakota
Name	Tongue River Formation
Geologic age	Phanerozoic \| Cenozoic \| Tertiary \| Paleocene
Original map label	Ttr
Primary rock type	sandstone
Secondary rock type	claystone
Other rock types	siltstone; coal
Lithologic constituents	Major Sedimentary > Clastic > Siltstone (Bed) Sedimentary > Clastic > Mudstone > Claystone (Bed) Sedimentary > Clastic > Sandstone (Bed) Minor Sedimentary > Coal (Bed)
Map references	Martin, J. E., Sawyer, J. F., Fahrenbach, M. D., Tomhave, D. W., and Schulz, L. D., 2004, Geologic Map of South Dakota: South Dakota Geological Survey
Unit references	Martin, J. E., Sawyer, J. F., Fahrenbach, M. D., Tomhave, D. W., and Schulz, L. D., 2004, Geologic Map of South Dakota: South Dakota Geological Survey
Geographic coverage	Harding - Perkins