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Greenhorn Formation and Belle Fourche and Mowry Shale

GREENHORN FORMATION AND BELLE FOURCHE AND MOWRY (Kmr) SHALE. GREENHORN FORMATION--Light-colored limestone, marl, and limy sandstone interbedded with gray concretionary shale. BELLE FOURCHE SHALE--Black soft bentonitic concretionary shale. MOWRY SHALE (AGE 94 TO 98 Ma)--Silvery-gray hard siliceous shale containing abundant fish scales and bentonite beds.
State Wyoming
Name Greenhorn Formation and Belle Fourche and Mowry Shale
Geologic age Phanerozoic | Mesozoic | Cretaceous-Early
Primary rock type mixed clastic/carbonate
Secondary rock type fine-grained mixed clastic
Other rock types mixed clastic/volcanic
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale
Minor
Sedimentary > Carbonate > Limestone
Unconsolidated > Marl
Sedimentary > Clastic > Sandstone
Incidental
Sedimentary > Clastic > Mudstone > Claystone > Bentonite
Map references
Love, J.D. and Christiansen, Ann Coe, 1985, Geologic Map of Wyoming: U.S. Geological Survey.
Unit references
Love, J.D. and Christiansen, Ann Coe, 1985, Geologic Map of Wyoming: U.S. Geological Survey.
Counties Crook - Niobrara - Weston