Nautiloid
Beloitoceras plebium
Middle Ordovician (Platteville)
Grand Detour Formation
Rock County WI USA
48mm nautiloid.

Nautiloid. Cephalopod.

Beloitoceras is a genus of nautiloid known from the Ordovician of various parts of the world (North America, Europe, China, and Australia). It lived at a time when nautiloids were becoming the apex predators of the seas.