Geologic units in Bollinger county, Missouri

Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (Early Ordovician-Ibexian Series) at surface, covers 49 % of this area

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

Roubidoux Formation (Early Ordovician-Ibexian Series) at surface, covers 26 % of this area

Sandstone, chert and interbedded dolomite

Gasconade Dolomite (Early Ordovician-Ibexian Series) at surface, covers 13 % of this area

Coarse - crystalline cherty dolomite with a basal Gunter Sandstone Member.

Holocene series (Quaternary-Holocene Series) at surface, covers 9 % of this area

Alluvium - clay, silt, sand, and gravel.

Eminence Dolomite, Potosi Dolomite (Late Cambrian-Croixian Series) at surface, covers 2 % of this area

Eminence Dolomite - dolomite with some druse - coated chert. Potosi Dolomite - dolomite with abundance of druse - coated chert.

St. Peter Sandstone, Everton Formation (Middle Ordovician to Early Ordovician) at surface, covers 1 % of this area

St. Peter Sandstone, Everton Formation

Gulfian Series (Late Cretaceous-Gulfian) at surface, covers 0.1 % 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.

Elvins Group - (including Derby-Doerun Dolomite, Davis Formation), Bonneterre Dolomite (Late Cambrian-Croixian Series) at surface, covers < 0.1 % of this area

Derby-Doerun Dolomite - alternating thin dolomite, siltstone, and shale; Davis Formation - glauconitic shale with fine - grained sandstone, limestone, and dolomite); Bonneterre Dolomite - dolomite, dolomitic limestone, and limestone; glauconitic in lower part.

St. Francois Mountains intrusive suite (subvolcanic, alkali granitic ring complexes) (Precambrian Y) at surface, covers < 0.1 % of this area

St. Francois Mountains intrusive suite (subvolcanic, alkali granitic ring complexes).

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.

Leemon Formation, Maquoketa Group, Cape Limestone, Kimmswick Limestone, Noix-Cyrene Limestone, Maquoketa Shale (Late Ordovician to Middle Ordovician) at surface, covers < 0.1 % 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.

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.

Undifferentiated (Ordovician rocks) (Ordovician) at surface, covers < 0.1 % of this area

Undifferentiated (Ordovician rocks)