Geologic units in Floyd county, Indiana

Borden Group (Mississippian) at surface, covers 61 % of this area

Mostly siltstone; lenses of crinodial limestone in upper part. Much cherty and silty limestone and dolomite in northwest. NP, top of New Providence Shale

Sanders Group (Mississippian) at surface, covers 23 % of this area

Mostly skeletal limestone, cherty in lower part

New Albany Shale (Devonian-Mississippian) at surface, covers 9 % of this area

Black and greenish-gray shale

Blue River Group (Mississippian) at surface, covers 8 % of this area

Mostly micritic, skeletal, and oolitic limestone

West Baden Group (Mississippian) at surface, covers 0.3 % of this area

Shale, sandstone, and micritic and skeletal limestone

Alluvium (Pleistocene to Holocene) at surface, covers < 0.1 % of this area

Alluvium; includes glacial deposits along the Ohio River and its tributaries west of Cannelton locks

Muscatatuck Group (Devonian) at surface, covers < 0.1 % of this area

Limestone and dolomite