Oil shales in Kentucky are rocks of predominantly Devonian age. The most prominant are the Ohio, Chattanooga, and New Albany Shales. A leaching study was done on six fresh oil shale samples and one retorted oil shale sample. Leaching reagents were distilled water, 0.0005 N sulfuric acid, and 0.05 N sulfuric acid. The concentration of constituents in the leachates were highly variable. The concentration of sodium, manganese, and zinc in the retorted shale leachate was several orders of magnitude higher than those of the leachates of fresh shale samples. The major oil shale outcrop covers approximately 1,000 square miles in a horseshoe pattern from Vanceburg, Lewis County , in the east, to Louisville, Jefferson County, in the west. The Kentucky, Red, and Licking Rivers cross the outcrop belt, the Rolling Fork River flows along the strike of the shale in the southwest part of the outcrop, and the Ohio River flows past the outcrop at the ends of the horseshoe. Oil shale does not appear to significantly alter the water quality of these streams. Oil shale is not an aquifer, but seeps and springs found in the shale indicate that water moves through it. Ground water quality is highly variable. (USGS)