Geologic units in Dearborn county, Indiana

Dillsboro Formation (Ordovician) at surface, covers 67 % of this area

Skeletal limestone and calcareous shale

Kope Formation (Ordovician) at surface, covers 17 % of this area

Shale and thin skeletal limestone

Whitewater Formation (Ordovician) at surface, covers 16 % of this area

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

Kope Formation (Ordovician) at surface, covers < 0.1 % of this area

Shale (75%) and limestone (25%) interbedded; gray to bluish gray weathers light gray to yellowish gray; planar, thin to thick bedded; 200 to 260 feet thick.

Point Pleasant Formation (Ordovician) at surface, covers < 0.1 % of this area

Limestone (60%) and shale (40%) interbedded; gray to bluish gray weathers light gray; planar to lenticular, thin to medium bedded; 0 to 80 feet thick.

Grant Lake and Fairview Formations, Miamitown Shale, Undivided (Ordovician) at surface, covers < 0.1 % of this area

Limestone (50%) and shale (50%), interbedded; gray to bluish-gray weathers light gray to yellowish-gray;, planar to lenticular, thin to medium bedded in lower half; wavy to irregular to nodular, thin to thick bedded in upper half; fossiliferous. Interval of shale (90%) with limestone (10%), as much as 35 feet thick, near middle of unit.

Waynesville and Arnheim Formations, Undivided (Ordovician) at surface, covers < 0.1 % of this area

Waynesville Formation, shale (70%) and limestone (30%) interbedded; gray to bluish gray weathers light gray; planar to irregular, thin to thick bedded; 90 to 120 feet thick. Arnheim formation, shale (60%) and limestone (40%) interbedded; gray to bluish gray weathers light gray; planar, wavy, irregular, to nodular (in upper portion), thin to thick bedded; 50 to 100 feet thick. Contains multiple sedimentary cycles consisting of the alternation of shale and limestone displaying planar to irregular bedding with limestone and shale exhibiting wavy to nodular bedding. Ranges from 140 to 220 feet. 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).

Alluvium (Pleistocene to Holocene) at surface, covers < 0.1 % of this area

Alluvium; includes glacial deposits along the Ohio River and its tributaries west of Cannelton locks

Garrard Siltstone and Kope and Clays Ferry Formations, undivided (Ordovician) at surface, covers < 0.1 % of this area

Garrard Siltstone and Kope and Clays Ferry Formations, undivided