Alluvial deposits of present streams
Alluvial deposits on one or more terrace levels
Brown lignitic clays, silts and sands; some sideritic glauconite may weather to brown ironstone in lower part.
Gray to brownish gray clay and silty clay, reddish brown in the Red River Valley, some sand and gravel locally.
Greenish gray sideritic clay in upper part may weather to brown ironstone; yellow to brown clays and fossiliferous marl in lower part may weather to black soil. Ironstone concretions near base.