Map
showing predominately N-S and NW-SE orientations of glacial groove marks
on
exposed Sioux quartzite bedrock. (Locations are near present course of I-90 from Davison to Minnehaha counties).
Map courtesy of the South Dakota Geological Survey 1965-1969).
exposed Sioux quartzite bedrock. (Locations are near present course of I-90 from Davison to Minnehaha counties).
Map courtesy of the South Dakota Geological Survey 1965-1969).
