These sea shells are fossil sea shells, over 350 million years old . If you look carefully at the loose rock laying on the ground surface, and if you are lucky, you may see fossil sea shell remnants or imprints in the rock. Fossils can be found in the sandstone and shale rocks on the other Ranger Districts of the George Washington and Jefferson National Forests.
Some fossil beds contain fossil trees and plants.
Back in the Paleozoic Era, the area now occupied by the Forest west of I-81 was a vast sea located south of the Equator. The Blue Ridge was huge mountain range bordering this vast sea. The Blue Ridge supplied sand and silt to the beaches and near-shore waters. The marine creatures living on the sea floor were buried in the sand and silt, and preserved as fossils. You don't need a rock pick to find the fossils.