Geologic units in Vermilion Parish, Louisiana

Prairie Terraces (Pleistocene) at surface, covers 34 % of this area

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

Chenier Plain, Fresh Marsh (Holocene) at surface, covers 29 % of this area

Gray to brown to black clay and silt of high organic content.

Chenier Plain, Saline Marsh (Holocene) at surface, covers 18 % of this area

Gray to brown to black clay and silt of moderate organic content.

Prairie Terraces (Pleistocene) at surface, covers 15 % of this area

Light gray to light brown clay, sandy clay, silt, sand, and some gravels. Overlain by 1-9 meters of loess.

Alluvium (Holocene) at surface, covers 3 % of this area

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

Delta Plain, Saline Marsh (Holocene) at surface, covers 1 % of this area

Gray to black clay of very high organic content, some peat.