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Permian, undifferentiated

Permian, undifferentiated: chert, sandstone, limestone, quartzite, and shale with rock phosphate mostly at base; mainly Phosphoria formation
State Montana
Name Permian, undifferentiated
Geologic age Phanerozoic | Paleozoic | Permian
Comments Pu? is not a unit shown on the source paper map, but was assigned by Raines and Johnson (1995) for unlabeled polygons thought to be this unit.
Primary rock type fine-grained mixed clastic
Secondary rock type carbonate
Other rock types chert; phosphorite; black shale; oil shale
Lithologic constituents
Map references
Ross, P.R., Andrews, D.A., and Witkind, I.J., 1955, Geologic map of Montana: U.S. Geological Survey, 2 sheets, scale 1:500,000.
Unit references
Raines, G.L. and Johnson, B.R., 1995, Digital representation of the Montana stage geologic map: a contribution to the Interior Columbia River Basin Ecosystem Management Project: U.S. Geological Survey Open-File Report 95-691, 21 p.;
Counties Broadwater