Dolostone, arenite, conglomerate, and chert; Silurian to Middle Ordovician marine outer continental-shelf deposits; east-central Idaho (IDSO;0)

State	Idaho
Name	Dolostone, arenite, conglomerate, and chert; Silurian to Middle Ordovician marine outer continental-shelf deposits; east-central Idaho
Geologic age	Silurian to Middle Ordovician
Original map label	SO
Comments	In the Dubois 1o x 2o quad, Saturday Mountain Fm and Laketown Dolomite comprise the SO unit. In the Idaho Falls 1o x 2o quad, Middle Ordovician Kinnikinic Quartzite also is included in the SO unit. Proportions of lithologies are estimated from information in Rupel and Lopez (1981). Churkin (1962) interprets Saturday Mtn. Fm as transitional between western eugeoclinal Phi Kappa Fm amd eastern miogeoclinal Fish Haven Dolomite. Similarly, the Laketown dolomite of central Idaho is transitional between western Trail Creek Fm and eastern miogeoclinal Laketown Dolomite. Kinnikinic Quartzite and Ramshorn Slate are transitional to miogeoclinal equivalents of the lower part of the Phi Kappa Fm.
Primary rock type	dolostone (dolomite)
Secondary rock type	arenite
Other rock types	conglomerate; chert
Lithologic constituents	Major Sedimentary > Carbonate > Dolostone (Lense)fossiliferous to cherty dolostone Minor Sedimentary > Clastic > Sandstone > Arenite (Bed) Incidental Sedimentary > Chemical > Chert (Lense)quartzite, pure, mostly medium-grained Sedimentary > Clastic > Conglomerate (Lense)
Map references	Bond, J.G., Kauffman, J.D., Miller, D.A., and Venkatakrishnan, Ramesh, 1978, Geologic map of Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology, with contributions from U.S. Geological Survey, scale 1:500,000.
Unit references	Bond, J.G., Kauffman, J.D., Miller, D.A., and Venkatakrishnan, Ramesh, 1978, Geologic map of Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology, with contributions from U.S. Geological Survey, scale 1:500,000. Rember, W.C., and Bennett, E.H., 1979, Geologic map of the Dubois quadrangle, Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology Map Series, Dubois 2o quadrangle, scale 1:250,000. Rember, W.C., and Bennett, E.H., 1979, Geologic map of the Idaho Falls quadrangle, Idaho: Moscow, Idaho, Idaho Bureau of Mines and Geology, Geologic Map Series, Idaho Falls 2o quadrangle, scale 1:250,000. Rupel, E.T. and Lopez, D.A., 1981, Geologic map of the Gilmore quadrangle, Lemhi and Custer Counties, Idaho: U.S. Geological Survey Geologic quadrangle Map GQ-1543, scale 1:62,500. [http://pubs.er.usgs.gov/publication/gq1543]
Geographic coverage	Butte - Clark - Custer - Lemhi