Geologic units in Crawford county, Missouri

Gasconade Dolomite (Early Ordovician-Ibexian Series) at surface, covers 34 % of this area

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

Roubidoux Formation (Early Ordovician-Ibexian Series) at surface, covers 29 % of this area

Sandstone, chert and interbedded dolomite

Eminence Dolomite, Potosi Dolomite (Late Cambrian-Croixian Series) at surface, covers 20 % of this area

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

Pennsylvanian Undifferentiated (Pennsylvanian) at surface, covers 9 % of this area

Pennsylvanian Undifferentiated

Smithville Dolomite, Powell Dolomite, Cotter Dolomite, Jefferson City Dolomite (Early Ordovician-Ibexian Series) at surface, covers 8 % of this area

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

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.