Geologic units in Scott county, Missouri

Holocene series (Quaternary-Holocene Series) at surface, covers 78 % of this area

Alluvium - clay, silt, sand, and gravel.

St. Peter Sandstone, Everton Formation (Middle Ordovician to Early Ordovician) at surface, covers 8 % of this area

St. Peter Sandstone, Everton Formation

Gulfian Series (Late Cretaceous-Gulfian) at surface, covers 7 % 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 3 % 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.

Decorah Group, Plattin Group (Middle Ordovician-Mohawkian Series) at surface, covers 2 % of this area

Decorah Group, Plattin Group

Joachim Dolomite, Dutchtown Formation (Middle Ordovician-Mohawkian Series) at surface, covers 1 % of this area

Joachim Dolomite, Dutchtown Formation

Leemon Formation, Maquoketa Group, Cape Limestone, Kimmswick Limestone, Noix-Cyrene Limestone, Maquoketa Shale (Late Ordovician to Middle Ordovician) at surface, covers 0.9 % 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.

Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (Early Ordovician-Ibexian Series) at surface, covers 0.1 % of this area

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

Silurian system (Late Silurian- to Early Silurian) at surface, covers < 0.1 % of this area

Joliet Limestone, Bowling Green Dolomite, Bryant Knob Formation, Bainbridge Formation, Sexton Creek Limestone.

Devonian System (Late to Early Devonian) at surface, covers < 0.1 % 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.

Kimmswick (Trenton) Limestone and Decorah Formation (Upper Ordovician (Stage 6)) at surface, covers < 0.1 % of this area

Kimmswick (Trenton) Limestone and Decorah Formation in southern and western Illinois.

Clayton Formation, Porters Creek Formation, Claiborne Formation, Wilcox Formation (Tertiary (Paleocene) to Tertiary (Pliocene)) at surface, covers < 0.1 % of this area

Clayton and Porters Creek Formations; Claiborne and Wilcox Formations.

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.