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Kootenai and Morrison Formations and Ellis Group

KOOTENAI AND MORRISON FORMATIONS AND ELLIS GROUP. KOOTENAI FORMATION--Rusty thin-bedded sandstone, grayish-red soft claystone, white limestone, and chert-pebble conglomerate. MORRISON FORMATION in northern Yellowstone area--Variegated silty claystone and fine-grained sandstone. ELLIS GROUP includes SWIFT, RIERDON, and SAWTOOTH FORMATIONS. Swift Formation--Calcareous glauconitic sandstone and sandy limestone. Rierdon Formation--Mudstone, siltstone, shale, and basal limestone. Sawtooth Formation--Red beds and limestone.
State Wyoming
Name Kootenai and Morrison Formations and Ellis Group
Geologic age Phanerozoic | Mesozoic | Jurassic-Middle Jurassic-Late(?) Cretaceous-Early
Primary rock type fine-grained mixed clastic
Secondary rock type medium-grained mixed clastic
Other rock types limestone; conglomerate
Lithologic constituents
Minor
Sedimentary > Clastic > Sandstone
Sedimentary > Clastic > Mudstone > Claystone
Sedimentary > Clastic > Conglomerate
Sedimentary > Carbonate > Limestone
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Mudstone
Sedimentary > Clastic > Siltstone
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 Park