2.5" Ordovician Oncoceratid & Gastropod Fossil Association - Wisconsin

Ordovician Oncoceratid & Gastropod Fossil Association - Wisconsin #215199

This is a 2.5" wide oncoceratid (Beloitoceras sp.) and gastropod (Clathrospira subconicae) fossil association, collected from Wisconsin. The fossils are part of an old collection from the Grand Detour Formation in Rock County.

Oncoceratids are curved nautiloid cephalopods that have been identified from the Middle Ordovician up to the Late Silurian. Richardsonoceras is known for having a stronger convex curvature than other cephalopods in the family Oncoceratidae.