Geologic units in Allen Parish, Louisiana

Alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene) at surface, covers 21 % of this area: gray to brownish gray clay and silty clay, reddish brown in the Red River Valley, some sand and gravel locally.
Lithology: clay or mud; sand; gravel
High Terraces (Phanerozoic | Cenozoic | Quaternary | Pleistocene) at surface, covers 6 % of this area: tan to orange clay, silt, and sand with a large amount of basal gravels.
Lithology: clay or mud; silt; sand; gravel
Intermediate Terraces (Phanerozoic | Cenozoic | Quaternary | Pleistocene) at surface, covers 36 % of this area: light gray to orange-brown clay, sandy clay, and silt; much sand and gravel locally.
Lithology: clay or mud; silt; sand; gravel
Prairie Terraces (Phanerozoic | Cenozoic | Quaternary | Pleistocene) at surface, covers 31 % of this area: light gray to light brown clay, sandy clay, silt, sand, and some gravels.
Lithology: clay or mud; silt; sand; gravel
Deweyville Terrace (Phanerozoic | Cenozoic | Quaternary | Pleistocene) at surface, covers 5 % of this area: gray mixed with brown-to-red clay and silty clay; some sand and gravel locally.
Lithology: clay or mud; sand; gravel