Geologic units in Scott county, Arkansas

Atoka Formation - Lower part (Middle Pennsylvanian- Atokan) at surface, covers 37 % of this area

Atoka Formation - Lower part

Atoka Formation - Middle part (Middle Pennsylvanian- Atokan) at surface, covers 21 % of this area

Atoka Formation - Middle part

Atoka Formation - Upper part (Middle Pennsylvanian- Atokan) at surface, covers 12 % of this area

Atoka Formation - Upper part

McAlester Formation (Middle Pennsylvanian- Des Moinesian) at surface, covers 11 % of this area

McAlester Formation

Johns Valley Shale (Early Pennsylvanian- Morrowan) at surface, covers 7 % of this area

Johns Valley Shale

Jackfork Sandstone (Early Pennsylvanian- Morrowan) at surface, covers 6 % of this area

Jackfork Sandstone

Savanna Formation (Late Pennsylvanian- Des Moinesian) at surface, covers 4 % of this area

Savanna Formation

Harthshorne Sandstone (Middle Pennsylvanian- Des Moinesian) at surface, covers 2 % of this area

Harthshorne Sandstone

Stanley Shale (Early Mississippian) at surface, covers 0.5 % of this area

Stanley Shale - Includes Chickasaw Creek Chert equivalent of Harlton (1938) near top and Hatton Tuff Lentil and Hot Springs Sandstone Member near base