Lance Formation

Orangish brown, coarse- to fine-grained sandstone with subordinate interbeds of shale and mudstone. Laterally equivalent to Hell Creek Formation. Fluvial. Thickness as much as 150 m (492 ft).
State Montana
Name Lance Formation
Geologic age Cretaceous
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone (Bed)
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)
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 Beaverhead - Big Horn - Carbon - Golden Valley - Musselshell - Rosebud - Stillwater - Treasure - Wheatland - Yellowstone