Geology of the County

In Daviess County, water is obtained from consolidated sedimentary rocks of Pennsylvanian age and from unconsolidated sediments of Quaternary age. Geologists call the oldest rocks found at the surface in Daviess County the Tradewater Formation. Pennsylvanian sediments were deposited 320 million years ago. The warm climate of the Pennsylvanian Period allowed extensive forests and great coastal swamps to form at the edges of water bodies. Marine waters advanced and receded many times, which produced many layers of sandstone, shale, and coal. Vegetation of all sorts fell into the water and was buried under blankets of sediments, which over long geologic time were compressed into coal. The nonvegetative sediments such as sand, clay, and silt were compressed into sandstone and shale. Over the last million years, Quaternary sediments have been deposited along the larger streams and rivers.

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

Coals, sandstones, and shales
McLeansboro Group (Mattoon, Bond, Patoka and Shelburn Formations), formerly the Sturgis Formation (Ps)
Carbondale Formation (Pc)
Tradewater Formation (Pt)

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

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