Geologic units in Lincoln Parish, Louisiana

Additional scientific data in this geographic area

Cook Mountain Formation (Eocene) at surface, covers 42 % of this area

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.

Cockfield Formation (Eocene) at surface, covers 38 % of this area

Brown lignitic clays, silts and sands; some sideritic glauconite may weather to brown ironstone in lower part.

Alluvium (Holocene) at surface, covers 19 % of this area

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

Prairie Terraces (Pleistocene) at surface, covers 0.3 % of this area

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