Frontier Formation and Mowry and Thermopolis Shales

Frontier Formation (Kf) - Gray sandstone and sandy shale. In Northern Yellowstone area, Yellowish- to medium-gray sandstone; tuffaceous and carbonaceous in lower part. Mowry Shale (Kmr) - Silvery-gray hard siliceous shale containing abundant fish scales and bentonite beds. Thermopolis Shale - Black soft fissile shale; Muddy Sandstone Member at top.
State Wyoming
Name Frontier Formation and Mowry and Thermopolis Shales
Geologic age Lower Cretaceous-Upper Cretaceous
Lithologic constituents
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone
Sedimentary > Carbonate > Limestone
Igneous > Volcanic > Felsic-volcanic (Pyroclastic-tuff)
Sedimentary > Clastic > Mudstone > Claystone > Bentonite
NGMDB product
Counties Albany - Carbon - Converse - Fremont - Hot Springs - Johnson - Laramie - Park - Sheridan - Sublette - Teton