Geology of the County

In Carroll County, water is obtained from consolidated sedimentary rocks of Ordovician age and unconsolidated sediments of Quaternary age. The oldest rocks found on the surface in Carroll County form the Clays Ferry Formation, deposited in shallow seas 490 million years ago during the Ordovician Period. In the Late Ordovician, the seas became relatively shallow, as indicated by the amounts of mud (shale) in the sediments. When the waters were clear and warm, a profusion of animal life developed, particularly brachiopods and bryozoa. Over the last million years, unconsolidated Quaternary sediments have been deposited along the larger streams and rivers.

Geologic Formations in the County
Unconsolidated deposits
Alluvium (Qa) and glacial sediments (Qg)

Interbedded limestones and shales
Drakes Formation (Saluda Dolomite, Bardstown, Rowland Members) (Od) and Bull Fork Formation (Ob)
Grant Lake Limestone, Fairview Formation, Calloway Creek Limestone (Oaf)
Clays Ferry Formation (Okc)

Interbedded shales and limestones
Clays Ferry Formation (Okc)

For more information, see the definitions of geologic terms and rock descriptions, a geologic map of Carroll County, a summary of the geology of Kentucky, and a discussion of fossils and prehistoric life in Kentucky.

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