2.5" Ordovician Cephalopod (Proteoceras) Fossil - Wisconsin

This is a 2.5" long example of Proteoceras sp. This fossil is part of a collection from the Grand Detour Formation in Rock County, Wisconsin. Proteoceras was one of few species of straight-shelled cephalopods. This specimen exhibits minor crack repair from the extraction process but the fossil itself is quite impressive. It is a partial shell embedded in stone.