Geologic units in Jefferson county, Missouri

Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (Early Ordovician-Ibexian Series) at surface, covers 45 % of this area

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

Decorah Group, Plattin Group (Middle Ordovician-Mohawkian Series) at surface, covers 9 % of this area

Decorah Group, Plattin Group

Osagean Series (Early Mississippian-Osagean Series) at surface, covers 9 % of this area

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

St. Peter Sandstone, Everton Formation (Middle Ordovician to Early Ordovician) at surface, covers 7 % of this area

St. Peter Sandstone, Everton Formation

Eminence Dolomite, Potosi Dolomite (Late Cambrian-Croixian Series) at surface, covers 6 % of this area

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

Joachim Dolomite, Dutchtown Formation (Middle Ordovician-Mohawkian Series) at surface, covers 5 % of this area

Joachim Dolomite, Dutchtown Formation

Roubidoux Formation (Early Ordovician-Ibexian Series) at surface, covers 5 % of this area

Sandstone, chert and interbedded dolomite

Meramecian Series (Late Mississippian-Meramecian Series) at surface, covers 4 % of this area

St. Louis Limestone, Salem Formation, Warsaw Formation.

Leemon Formation, Maquoketa Group, Cape Limestone, Kimmswick Limestone, Noix-Cyrene Limestone, Maquoketa Shale (Late Ordovician to Middle Ordovician) at surface, covers 4 % 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.

Gasconade Dolomite (Early Ordovician-Ibexian Series) at surface, covers 3 % of this area

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

Holocene series (Quaternary-Holocene Series) at surface, covers 2 % of this area

Alluvium - clay, silt, sand, and gravel.

Devonian System (Late to Early Devonian) at surface, covers 0.6 % 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.

Elvins Group - (including Derby-Doerun Dolomite, Davis Formation), Bonneterre Dolomite (Late Cambrian-Croixian Series) at surface, covers 0.5 % 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.

Ancell Group (Middle Ordovician (Darriwillian) to Upper Ordovician (Stage 5)) at surface, covers 0.2 % of this area

Ancell Group, includes St. Peter Sandstone, Dutchtown Limestone, Joachim Dolomite, and Glenwood Formation; includes Prairie du Chien Group in Jo Daviess County of northwestern Illinois.

Platteville Group (Upper Ordovician (Stage 5)) at surface, covers < 0.1 % of this area

Platteville Group, includes Pecatonica, Mifflin, Grand Detour, Nachusa, and Quimbys Mill Formations; includes Plattin Limestone in southwestern Illinois.

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.

Kinderhookian Series (Early Mississippian-Kinderhookian Series) at surface, covers < 0.1 % of this area

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

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

Pennsylvanian Undifferentiated