McAlester Formation
(Middle Pennsylvanian- Des Moinesian) at surface, covers 9 % of this area McAlester Formation
Harthshorne Sandstone
(Middle Pennsylvanian- Des Moinesian) at surface, covers 7 % of this area Harthshorne Sandstone
Savanna Formation
(Late Pennsylvanian- Des Moinesian) at surface, covers 4 % of this area Savanna Formation
Alluvium
(Holocene) at surface, covers 3 % of this area Alluvial deposits of present streams
Terrace deposits
(Late Pleistocene) at surface, covers 1 % of this area Alluvial deposits on one or more terrace levels