Geologic units in Lewis county, Missouri

Meramecian Series (Late Mississippian-Meramecian Series) at surface, covers 63 % of this area

St. Louis Limestone, Salem Formation, Warsaw Formation.

Osagean Series (Early Mississippian-Osagean Series) at surface, covers 31 % of this area

Keokuk Limestone, Burlington Limestone, Elsey Formation, Reeds Spring Formation, Pierson Limestone, Fern Glen Formation.

Holocene series (Quaternary-Holocene Series) at surface, covers 6 % of this area

Alluvium - clay, silt, sand, and gravel.

Riverton Formation, Burgner Formation (Middle Pennsylvanian-Atokan Stage) at surface, covers 0.3 % of this area

Shale, clay, coal. Burgner Formation - limestone.

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone (Mississippian (Tourniaisian to Visean)) at surface, covers < 0.1 % of this area

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone.

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone (Middle Devonian (Givetian) to Upper Devonian (Fammenian)) at surface, covers < 0.1 % of this area

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone.

Glen Park Formation, Hannibal Shale, Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone (Mississippian (Tourniaisian)) at surface, covers < 0.1 % of this area

Glen Park Formation, Hannibal Shale, Chouteau Limestone, McCraney Limestone, Prospect Hill Siltstone, and Starrs Cave Limestone.