Horsethief Formation

Gray to light brown, medium- to coarse-grained, locally titaniferous sandstone with argillaceous sandstone and mudstone near base. Brackish to littoral marine. Thickness as much as 60 m (197 ft).
State Montana
Name Horsethief Formation
Geologic age Cretaceous
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone (Bed)
Minor
Sedimentary > Clastic > Mudstone (Bed)
References

Vuke, S.M., Porter, K.W., Lonn, J.D., and Lopez, D.A., 2007, Geologic Map of Montana - Compact Disc: Montana Bureau of Mines and Geology: Geologic Map 62-C, 73 p., 2 sheets, scale 1:500,000. This map was digitized in 2012 as a result of a contract between the U.S. Geological Survey and the Montana Bureau of Mines and Geology.

NGMDB product
Counties Glacier - Lewis and Clark - Pondera - Teton