Quadrant Formation

Very light gray, yellowish or pinkish, well-sorted sandstone or quartzite, locally interbedded with subordinate limestone beds. Marine. Generally, thickness as much as 140 m (460 ft), but as much as 800 m(2,625 ft) in southwestern-most Montana.
State Montana
Name Quadrant Formation
Geologic age Pennsylvanian
Lithologic constituents
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Carbonate > Limestone (Bed)

Vuke, S.M., Porter, K.W., Lonn, J.D., and Lopez, D.A., 2007, Geologic Map of Montana - Compact Disc: Montana Bureau of Mines and Geology: Geologic Map 62-C, 73 p., 2 sheets, scale 1:500,000. This map was digitized in 2012 as a result of a contract between the U.S. Geological Survey and the Montana Bureau of Mines and Geology.

NGMDB product
Counties Beaverhead - Cascade - Judith Basin - Madison - Meagher