Wikipedia
Gasconsoceras
Gasconsoceras is a genus of nautiloid cephalopod belonging to the tarphyceroid family Barrandeoceratidae, known from the Middle Silurian.
Shells of Gasconsoceras are rapidly enlarging gyrocones and serpenticones covered by fine transverse and longitudinal striae and prominent dorsal and lateral transverse ribs. A fair degree of mobility is indicated by the deep hyponomic sinus. Other than being between center and venter, the siphuncle is poorly known.