Geologic units in Ouachita county, Arkansas

Claibourne Group (Middle Eocene) at surface, covers 38 % of this area

Claibourne Group

Alluvium (Holocene) at surface, covers 30 % of this area

Alluvial deposits of present streams

Terrace deposits (Late Pleistocene) at surface, covers 17 % of this area

Alluvial deposits on one or more terrace levels

Wilcox Group (Early Eocene) at surface, covers 16 % of this area

Wilcox Group