Geologic units in Logan county, Kentucky

Rocks of Chesterian age, lower part (Upper Mississippian) at surface, covers 48 % of this area

Rocks of Chesterian age, lower part

Ste. Genevieve and St. Louis Limestones, undivided (Mississippian) at surface, covers 35 % of this area

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

Rocks of Chesterian age, upper part (Upper Mississippian) at surface, covers 9 % of this area

Rocks of Chesterian age, upper part

Alluvium (Pleistocene to Holocene) at surface, covers 5 % of this area

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

Caseyville Formation (Lower to Middle Pennsylvanian) at surface, covers 4 % of this area

Caseyville Formation