Pierre Shale

Blue-gray to dark-gray, fissile to blocky shale with persistent beds of bentonite, black organic shale, and light-brown chalky shale. Contains minor sandstone, conglomerate, and abundant carbonate and ferruginous concretions. Thickness up to 1,000 ft (305 m).
State South Dakota
Name Pierre Shale
Geologic age Upper Cretaceous
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Claystone > Bentonite (Bed)Fissile to blocky shale with persistent beds of bentonite
Sedimentary > Clastic > Mudstone > Shale (Bed)Blue-gray to dark-gray, fissile to blocky shale with persistent beds of bentonite, black organic shale, and light-brown chalky shale.
Minor
Sedimentary > Carbonate (Bed)Abundant carbonate and ferruginous concretions
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Clastic > Conglomerate (Bed)
References

Tomhave, D.W., and Schulz, L.D., 2004, Bedrock Geologic Map Showing Configuration of the Bedrock Surface in South Dakota East of the Missouri River, South Dakota Geological Survey, GM 9, scale 1:500,000.

NGMDB product
Counties Aurora - Beadle - Bon Homme - Brookings - Brown - Brule - Buffalo - Butte - Campbell - Charles Mix - Clark - Codington - Corson - Custer - Davison - Day - Deuel - Dewey - Douglas - Edmunds - Fall River - Faulk - Grant - Gregory - Haakon - Hamlin - Hand - Harding - Hughes - Hutchinson - Hyde - Jackson - Jerauld - Jones - Kingsbury - Lake - Lyman - McCook - McPherson - Marshall - Meade - Mellette - Miner - Moody - Pennington - Potter - Roberts - Sanborn - Shannon - Spink - Stanley - Sully - Todd - Tripp - Turner - Walworth - Yankton - Ziebach