Geologic units in Red River Parish, Louisiana

Natural Levees (Holocene) at surface, covers 36 % of this area

Gray and brown silt, silty clay, some very fine sand, reddish brown along the Red River.

Alluvium (Holocene) at surface, covers 20 % of this area

Gray to brownish gray clay and silty clay, reddish brown in the Red River Valley, some sand and gravel locally.

Intermediate Terraces (Pleistocene) at surface, covers 19 % of this area

Light gray to orange-brown clay, sandy clay, and silt; much sand and gravel locally.

Wilcox Group (undifferentiated) (Paleocene) at surface, covers 16 % of this area

Gray to brown lignitic sands and silty to sandy lignitic clays, many seams of lignite; some limestone and glauconite.

High Terraces (Pleistocene) at surface, covers 7 % of this area

Tan to orange clay, silt, and sand with a large amount of basal gravels.

Prairie Terraces (Pleistocene) at surface, covers 2 % of this area

Light gray to light brown clay, sandy clay, silt, sand, and some gravels.