Geologic units in Todd county, Kentucky

Ste. Genevieve and St. Louis Limestones, undivided (Mississippian) at surface, covers 41 % of this area

Ste. Genevieve and St. Louis Limestones, undivided; includes Salem Limestone west of Christian County

Rocks of Chesterian age, lower part (Upper Mississippian) at surface, covers 39 % of this area

Rocks of Chesterian age, lower part

Rocks of Chesterian age, upper part (Upper Mississippian) at surface, covers 10 % of this area

Rocks of Chesterian age, upper part

Caseyville Formation (Lower to Middle Pennsylvanian) at surface, covers 9 % of this area

Caseyville Formation

Alluvium (Pleistocene to Holocene) at surface, covers 0.4 % of this area

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