Geologic units in Union county, Indiana

Dillsboro Formation (Ordovician) at surface, covers 47 % of this area

Skeletal limestone and calcareous shale

Whitewater Formation (Ordovician) at surface, covers 47 % of this area

Skeletal limestone and calcareous shale; dolomitic mudstone (S, Saluda Member) at base

Louisville Limestone through Brassfield Limestone (Silurian) at surface, covers 5 % of this area

Sexton Creek Limestone at base in Kentland area and on cross-section

Drakes, Whitewater and Liberty Formations, Undivided (Ordovician) at surface, covers < 0.1 % of this area

Drakes Formation; shale (90%) and limestone/dolomite (10%), interbedded; gray and maroon, weathers yellowish gray; planar to irregular, thin to thick bedded; 20 to 30 feet thick. Whitewater Formation, limestone (60%) and shale (40%) interbedded; gray weathers yellowish gray; irregular to wavy, thin to medium bedded; 20 to 80 feet thick. Liberty Formation, limestone (50%) and shale (50%), interbedded; gray weathers yellowish gray; planar to irregular, thin to medium bedded; 20 to 40 feet thick. Interval ranges from 60 to 150 feet in thickness. The Geological Survey of Ohio recognizes the Cincinnati Group proposed by Meek and Worthen (1865), but at this time retains it as an informal term. The unit will be formally reinstated as a lithostratigraphic term after revision of its lower boundary and minor lithologic redescription of its units are completed. The ten formations included in the group are the (ascending) Clays Ferry Formation, the Kope Formation, the Fairview Formation, the Miamitown Shale, the Grant Lake Limestone, the Arnheim Formation, the Waynesville Formation, the Liberty Formation, the Whitewater Formation, and the Drakes Formation. Six members have been identified in the course of field mapping: the Point Pleasant Tongue of the Clays Ferry, the informal Bellevue, Corryville, Mount Auburn, and Straight Creek members of the Grant Lake Limestone, and the Preachersville Member of the Drakes Formation. The Backbone Creek and Elk Creek beds are recognized as excellent stratigraphic marker beds (Shrake and others, 1988).