Variable deposits that range from pebble to boulder size and include sand, silt, and clay. Dominantly alluvial terrace, abandoned channel and floodplain, remnant alluvial fan, and local glacial outwash.
State Montana
Name Gravel
Geologic age Tertiary
Lithologic constituents
Unconsolidated > Coarse-detrital > Gravel (Alluvial, Glacial-outwash)
Unconsolidated > Coarse-detrital > Sand (Alluvial, Glacial-outwash)
Unconsolidated > Fine-detrital > Silt (Alluvial, Glacial-outwash)
Unconsolidated > Fine-detrital > Clay (Alluvial, Glacial-outwash)

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 - Big Horn - Blaine - Carter - Cascade - Chouteau - Daniels - Dawson - Gallatin - Judith Basin - McCone - Madison - Meagher - Phillips - Prairie - Richland - Roosevelt - Sheridan - Sweet Grass - Teton - Valley - Yellowstone