Gray to brown lignitic sands and silty to sandy lignitic clays, many seams of lignite; some limestone and glauconite.
Gray to brownish gray clay and silty clay, reddish brown in the Red River Valley, some sand and gravel locally.
Light gray to light brown clay, sandy clay, silt, sand, and some gravels.
Gray and brown silt, silty clay, some very fine sand, reddish brown along the Red River.
Light gray to orange-brown clay, sandy clay, and silt; much sand and gravel locally.
Wilcox Group, undivided