Niobrara and Frontier Formations, and Mowry and Thermopolis Shales (WYKnt;0)

NIOBRARA (Kn) AND FRONTIER (Kf) FORMATIONS, AND MOWRY (Kmr) AND THERMOPOLIS SHALES. NIOBRARA FORMATION (AGE ABOUT 83 Ma)--Light-colored limestone and gray to yellow speckled limy shale. FRONTIER FORMATION--Gray sandstone and sandy shale. MOWRY SHALE (AGE 94 TO 98 Ma)--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	Niobrara and Frontier Formations, and Mowry and Thermopolis Shales
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Early Cretaceous-Middle(?) Cretaceous-Late
Original map label	Knt
Primary rock type	sandstone
Secondary rock type	shale
Other rock types	mixed clastic/carbonate; mixed clastic/volcanic
Lithologic constituents	Minor Sedimentary > Clastic > Mudstone > Claystone > Bentonite Sedimentary > Carbonate > Limestone Sedimentary > Clastic > Mudstone > Shale Sedimentary > Clastic > Sandstone
Map references	Love, J.D. and Christiansen, Ann Coe, 1985, Geologic Map of Wyoming: U.S. Geological Survey. [http://pubs.er.usgs.gov/publication/ofr83802]
Unit references	Love, J.D. and Christiansen, Ann Coe, 1985, Geologic Map of Wyoming: U.S. Geological Survey. [http://pubs.er.usgs.gov/publication/ofr83802]
Geographic coverage	Laramie