Geologic units in Independence county, Arkansas

Cane Hill Member of Hale Formation (Early Pennsylvanian- Morrowan) at surface, covers 13 % of this area

Cane Hill Member of Hale Formation

Pitkin Limestone, Fayetteville Shale (including the Wedington Sandstone member), and Batesville Sandstone (including the Hindsville Limestone Member) (Late Mississippian- Chesterian) at surface, covers 12 % of this area

Pitkin Limestone, Fayetteville Shale (including the Wedington Sandstone member), and Batesville Sandstone (including the Hindsville Limestone Member)

Boone Formation (Early Mississippian- Meramecian to Osagean) at surface, covers 11 % of this area

Boone Formation

Alluvium - Alluvial deposits of local streams or of overbank flow of major streams (Holocene) at surface, covers 10 % of this area

Alluvial deposits of local streams or of overbank flow of major streams - In some areas includes deposits in abandoned meanders of major streams

Cason Shale and Fernvale Limestone (Upper Ordovician) and Kimmswick Limestone, Plattin Limestone, and Joachim Dolomite (Middle Ordovician) (Late Ordovician to Middle Ordovician) at surface, covers 9 % of this area

Cason Shale and Fernvale Limestone (Upper Ordovician) and Kimmswick Limestone, Plattin Limestone, and Joachim Dolomite (Middle Ordovician)

Bloyd Shale, and Prairie Grove Member of the Hale Formation (Middle Pennsylvanian- Morrowan) at surface, covers 7 % of this area

Bloyd Shale, and Prairie Grove Member of the Hale Formation

Moorefield Formation (Late Mississippian- Meramecian) at surface, covers 6 % of this area

Moorefield Formation

Alluvium and terrace deposits (Holocene to Pleistocene) at surface, covers 6 % of this area

Alluvial deposits of present streams and on one or more terrace levels

St. Peter Sanstone and Everton Formation (Middle Ordovician) (Middle Ordovician) at surface, covers 5 % of this area

St. Peter Sanstone and Everton Formation (Middle Ordovician)

Alluvium - Alluvial deposits in major stream channels or in mappable meanders of major streams (Holocene) at surface, covers 5 % of this area

Alluvial deposits in major stream channels or in mappable meanders of major streams - Includes alluvial deposits in natural levees in some areas.

Cretaceous rocks (Cretaceous) at surface, covers 4 % of this area

Cretaceous rocks

Ruddell Shale (Late Mississippian- Chesterian) at surface, covers 3 % of this area

Ruddell Shale

Chattanooga Shale (Lower Mississippian and Upper Devonian), Clifty Limestone (Middle Devonian), and Penters Chert (Lower Devonian) (Early Mississippian to Early Devonian) at surface, covers 3 % of this area

Chattanooga Shale (Lower Mississippian and Upper Devonian), Clifty Limestone (Middle Devonian), and Penters Chert (Lower Devonian)

Terrace deposits (Late Pleistocene) at surface, covers 3 % of this area

Alluvial deposits on one or more terrace levels

Gravel (Tertiary) at surface, covers 1 % of this area

Gravel on isolated hills within 40 miles (64km) of the Mississippi Embayment. Many small deposits to the west not shown

Lafferty, St. Clair and Brassfield Limestones (Late Silurian to Early Silurian) at surface, covers 0.5 % of this area

Lafferty, St. Clair and Brassfield Limestones