Geologic units in Ralls county, Missouri

Osagean Series (Early Mississippian-Osagean Series) at surface, covers 36 % of this area

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

Kinderhookian Series (Early Mississippian-Kinderhookian Series) at surface, covers 22 % of this area

Northview Shale, Sedalia Formation, Compton Limestone, Bachelor Formation Chouteau Group, Hannibal Shale, Horton Creek Limestone.

Cherokee Group - Cabaniss Subgroup, Krebs Subgroup (Middle Pennsylvanian-Middle Series-Desmonian Stage) at surface, covers 18 % of this area

Cabaniss Subgroup - cyclic deposits, shale, sandstone, clay and several workable coal beds. Krebs Subgroup - cyclic deposits, sandstone, siltstone, shale, clay and some workable coal beds.

Leemon Formation, Maquoketa Group, Cape Limestone, Kimmswick Limestone, Noix-Cyrene Limestone, Maquoketa Shale (Late Ordovician to Middle Ordovician) at surface, covers 11 % of this area

Leemon Formation, Maquoketa Group including: (Girardeau Limestone, Orchard Creek Shale, Thebes Sandstone, Cape La Croix Shale), Cape Limestone, Kimmswick Limestone, Noix-Cyrene Limestone, Maquoketa Shale.

Marmaton Group (Middle Pennsylvanian-Middle Series-Desmonian Stage) at surface, covers 8 % of this area

Cyclic deposits, shale and limestone with sandstone, clay and several coal beds, some workable.

Devonian System (Late to Early Devonian) at surface, covers 4 % of this area

Chattanooga Shale, Sylamore Sandstone, Fortune Formation, Holts Summit Sandstone, Snyder Creek Shale, Cedar Valley Limestone, Louisiana Limestone, Saverton Shale, Grassy Creek Shale, Turpin Sandstone, Bushberg Sandstone, Glen Park Limestone, St. Larent Limestone, Beauvais Sandstone, Grand Tower Limestone, Clear Creek Chert, Little Saline Limestone, Grassy Knob Chert, Bailey Formation.

Decorah Group, Plattin Group (Middle Ordovician-Mohawkian Series) at surface, covers 1 % of this area

Decorah Group, Plattin Group

Holocene series (Quaternary-Holocene Series) at surface, covers 0.5 % of this area

Alluvium - clay, silt, sand, and gravel.

Maquoketa Formation or Group (Upper Ordovician (Stage 6 to Hirnatian)) at surface, covers < 0.1 % of this area

Maquoketa Formation or Group, includes Cape Limestone, Cape La Croix Shale, Thebes Sandstone, Orchard Creek Shale, Girardeau Limestone, and Leemon Formation in southern Illinois; includes Scales Shale, Fort Atkinson Limestone, Brainard Shale, and Neda Formation in northern Illinois; includes Noix Oolite in western Illinois.