The general geology of Jefferson County is very similar to that of other counties lying along the fringes of the Outer Bluegrass area -- that is to say, bedrocks are more-or-less horizontally stratified and consist principally of limestones and shales. The present topography is largely the result of erosion; the soil mantles are residual products of weathering of the uppermost stratum of bedrock or shale (as the case may be).
The unique features of the area are associated with the Ohio River and outwashes resulting from encroachments of two glaciations. The toe or southern boundary of ice did not cross the River in this area; but the mouth of the Salt River was blocked; and the deeper channel was filled with a mantle of sediment. This sediment might be encountered in the channel of Floyd's Fork and other tributaries and streams in the county; The westward flow of outwash deposited sands and gravels, etc., in the Ohio River valley; and these materia ls occur as two, fairly distinct terraces or flood plains along the interior arcs of meanders.
Digital Object Identifier
Havens, James H. and Deen, Robert C., "A General Study of Highway Construction Materials Jefferson County (A Pilot Study)" (1965). Kentucky Transportation Center Research Report. 1215.