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Madison Group and Darby Formation (TB, N) or Madison Group and Three Forks and Jefferson Formations (Y)

MADISON GROUP AND DARBY FORMATION (Thrust Belt, north Wyoming). MADISON GROUP--Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). DARBY FORMATION--Yellow and greenish-gray shale and dolomitic siltstone underlain by fetid brown dolomite and limestone. MADISON GROUP AND THREE FORKS AND JEFFERSON FORMATIONS (Yellowstone). MADISON GROUP--Group includes Mission Canyon Limestone (blue-gray massive limestone and dolomite), underlain by Lodgepole Limestone (gray cherty limestone and dolomite). THREE FORKS FORMATION--Pink, yellow, and green dolomitic siltstone and shale. JEFFERSON FORMATION--Massive siliceous dolomite.
State Wyoming
Name Madison Group and Darby Formation (TB, N) or Madison Group and Three Forks and Jefferson Formations (Y)
Geologic age Phanerozoic | Paleozoic | Devonian-Late Carboniferous Mississippian-Early(?) Mississippian-Middle(?) Mississippian-Late
Primary rock type limestone
Secondary rock type dolostone (dolomite)
Other rock types mudstone
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone
Sedimentary > Carbonate > Dolostone
Minor
Sedimentary > Clastic > Mudstone > Shale
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 Big Horn - Fremont - Hot Springs - Johnson - Lincoln - Park - Sheridan - Sublette - Teton - Washakie