Geologic units in Stoddard county, Missouri

Holocene series (Quaternary-Holocene Series) at surface, covers 77 % of this area

Alluvium - clay, silt, sand, and gravel.

Gulfian Series (Late Cretaceous-Gulfian) at surface, covers 10 % of this area

Owl Creek Formation - massive, sandy, micaceous, fossilliferous, glauconitic marine clay, max 100 ft. McNairy Formation - unconsolidated sandstone with clay and gravel lenses, max of 250 ft.

Tertiary system (Tertiary-Late-Pliocene to Paleocene) at surface, covers 10 % of this area

Pliocene series - Mounds Gravel (Lafayette Formation) - ferruginous, chert gravel, max of 60 ft. Eocene series - Wilcox group - includes Holly Springs Formation - bedded sandstone, clay and gravel, max of 1200 ft.; Ackerman Formation - clay with lens of sand and gravel, max of 100ft. Paleocene series - Midway Group - includes Porters Creek Clay - bentonitic clay, max of 200 ft.; Clayton Formation - marl, fossiliferous, calcareous, limonitic, glauconitic sand and clay, max of 20 ft.

Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (Early Ordovician-Ibexian Series) at surface, covers 2 % of this area

Fine crystalline, silty, cherty dolomite, and oolitic chert with local sandstone beds.