Geologic units in Dallas county, Arkansas

Claibourne Group (Middle Eocene) at surface, covers 33 % of this area

Claibourne Group

Wilcox Group (Early Eocene) at surface, covers 28 % of this area

Wilcox Group

Alluvium (Holocene) at surface, covers 24 % of this area

Alluvial deposits of present streams

Terrace deposits (Late Pleistocene) at surface, covers 15 % of this area

Alluvial deposits on one or more terrace levels