Judith River Formation

Light brown to light gray, fine- to coarse-grained sandstone with interbeds of gray to black carbonaceous shale, silty shale, and thin coal. Local Parkman Sandstone Member (lower part of formation):yellowish gray to brownish gray and olive green, fine- to medium-grained, cross-bedded sandstone interbedded with yellowish gray, silty shale. Estuarine, brackish, and nearshore marine. Thickness as much as 305 m (1000 ft).
State Montana
Name Judith River Formation
Geologic age Cretaceous
Lithologic constituents
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Bed, Carbonaceous)
Sedimentary > Clastic > Mixed-clastic > Siltstone-mudstone (Bed)silty shale
Sedimentary > Coal (Bed)

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 Big Horn - Blaine - Carbon - Chouteau - Fergus - Garfield - Golden Valley - Hill - Judith Basin - Liberty - Meagher - Musselshell - Petroleum - Phillips - Rosebud - Stillwater - Sweet Grass - Toole - Treasure - Valley - Wheatland - Yellowstone