Alluvium

Clay to boulder-size clasts with locally abundant organic material. Thickness up to 75 ft (23m).
State South Dakota
Name Alluvium
Geologic age Quaternary
Lithologic constituents
Major
Unconsolidated > Fine-detrital (Alluvial)clay to boulder-sized clasts
Unconsolidated > Coarse-detrital (Alluvial)clay to boulder-sized clasts
References

Martin, J.E., Sawyer, J.F., Fahrenbach, M.D., Tomhave, D.W., and Schulz, L.D., 2004, Geologic Map of South Dakota: South Dakota Geological Survey, GM 10, scale 1:500,000.

NGMDB product
Counties Bennett - Brule - Butte - Charles Mix - Corson - Custer - Dewey - Fall River - Gregory - Haakon - Harding - Hughes - Jackson - Jones - Lawrence - Lyman - Meade - Mellette - Pennington - Perkins - Potter - Shannon - Stanley - Sully - Todd - Tripp - Walworth - Ziebach