Fossil Gastropod (Cyclonema) Cluster - Ohio

This is a cluster of Ordovician aged gastropods from the Arnheim Formation of Ohio. There are five nice specimens of the gastropod Cyclonema present along with fragments of several other fossils. Mollusc shells are typically composed of a phosphatic substance called Aragonite. Unfortunately Aragonite does not preserve well in the Cincinnatian, so most gastropod fossils are internal molds, unlike this specimen. This piece has been cleaned under microscope using air abrasives.