I found this on a mountain side more than 20 years ago now .It was about 1500 to 2000 feet above sea level according to the topo map for that area .There where numerous rocks scattered all over that area with the imprint of those small shells .
We find rocks similar to those in ohio and Kentucky, our geologist friend says that those area were once an ocean bed and later got pushed up by the movement of Teutonic plates so the sea bed was then the side of a mountain...or hill. Sounds reasonable. The ones in ohio are often found in stream beds southeast of Cincinnati. Trilobite fossils are quite common.