Beloitoceras carveri
Nautiloid
Ordovician
Mifflin Formation
Lee County, Illinois, USA

28mm nautiloid with small matrix.

Cephalopod. Mollusc.

Beloitoceras is a genus of straight-shelled nautiloid that lived during the Ordovician Period.  Its remains have been found in North America, Europe, and China.  It lived at a time when nautiloids were diversifying and becoming the apex predators of the seas.

Nice matrix piece.