Tan to orange clay, silt, and sand with a large amount of basal gravels.
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.
Light gray to orange-brown clay, sandy clay, and silt; much sand and gravel locally.
Gray and brown silt, silty clay, some very fine sand, reddish brown along the Red River.
Gray to white sandstones; loose quartz sand, tuffaceous sandstone, volcanic ash, and brown sandy clays; petrified wood locally.
Light gray to brown liginitic clays with thin interbeds of limonitic sands or lignite; near base,calcareous, glauconitic, and fossiliferous beds may weather to black soil.
Brown to gray liginitic clays with thin interbeds of lignite or micaceous sands; calcareous shale, petrified wood, and bluish fossilferous clay locally.
Yellow to gray siltstones, sandstones, and clays with thin tuffaceous beds; some lenses of black chert gravel; petrified wood locally.
Gray calcareous clays which may weather to black soil; siltstone, taffaceous clays and some volcanic ash beds
Brown lignitic clays, silts and sands; some sideritic glauconite may weather to brown ironstone in lower part.