Geologic units in Jackson Parish, Louisiana

Additional scientific data in this geographic area

Cockfield Formation (Eocene) at surface, covers 56 % 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 18 % of this area

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

Cook Mountain Formation (Eocene) at surface, covers 16 % 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.

Prairie Terraces (Pleistocene) at surface, covers 6 % of this area

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

Sparta Formation (Eocene) at surface, covers 3 % of this area

White to light gray massive sands with interbedded clays; some thin beds of lignite or lignitic sands and shales.