Barrandeoceras

Barrandeoceras is a large, coiled, Middle Ordovician nautiloid cephalopod and part of the Tarphycerida.

The shell is serpenticonic with whorls touching but not embracing.

The adult body chamber becomes freed of the preceding whorl, a rather common character among tarphycerids.

Grow lines show a distinct hyponomic sinus.

Barrandeoceras has been found in the Middle Ordovician of New York, Ontario, and Quebec.