Ceratopea billingsi (Gastropoda) from the Early Ordovician of Kronprins Christian Land, eastern North Greenland

The name Ceratopea is generally associated with a horn or claw-shaped operculum locally common in late Early Ordovician carbonates, the parent gastropod shell being much less well known (Yochelson & Bridge, 1958; Yochelson, 1979). Ceratopea is recorded from both North and East Greenland. Yochelson & Peel (1975) described C. ankylosa and C. unguis from the Wandel Valley Formation of Peary Land, eastem North Greenland, and the latter species also occurs in the Nunatami Formation of Washington Land, some 600 km to the west (Peel & Yochelson, 1979). In 1964, Yochelson described two species of Ceratopea from the Narwhale Sound Formation of East Greenland, one in open nomenclature and the second, a new species to which he gave the name C. billingsi.