Taft Hill Member of Blackleaf Formation

Black shale, gray bentonitic siltstone, and glauconitic sandstone. Marine. Thickness as much as 180 m (590 ft).
State Montana
Name Taft Hill Member of Blackleaf Formation
Geologic age Cretaceous
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Sedimentary > Clastic > Sandstone (Bed, Glauconitic)
Sedimentary > Clastic > Siltstone (Bed)
Incidental
Sedimentary > Clastic > Mudstone > Claystone > Bentonite (Bed)gray bentonitic siltstone
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 Cascade - Chouteau - Judith Basin