For the past few years, the Division of Research, as a part of its continuing study of the occurrence of landslides in Kentucky, has reviewed and studied several sites in order to identify and delineate the geologic and soil formations which might be involved in the unstable earth masses. After a study of a number of landslides, it became evident that one particular material was highly susceptible to the development of landslides. This material, in Eastern Kentucky, is known as the Crab Orchard Formation and was deposited during the middle Silurian age. The Crab Orchard Formation, a deposit some 50 to 120 feet thick, is extensively mapped in the eastern portion of the State and correlates geologically with the Osgood Formation mapped in the western portion of Kentucky. The Crab Orchard and Osgood Formations are primarily shale deposits with some thin, discontinuous beds of dolomite. Soils which typically develop from these formations include the Rockcastle, Rarden, Fleming, and Fawcett series.

Report Date


Report Number

No. 254

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The opinions, findings, and conclusions in this report are not necessarily those of the Department of Highways or the Bureau of Public Roads.