Publications

Restudy of the previously unassigned narrow conical genus Polylopia Clark discloses that it bears features which ally it most closely with the Scaphopoda. These are: (1) possession of a multi-layered wall, (2) presence of external longitudinal ribbing, and (3) truncation of the gradually tapering narrow cone. Characteristics diagnostic of other kinds of narrow conical shells as tentaculitids, styliolinids, hyolithids, conularids, pteropods, cephalopods, or worms are lacking and placement in any of these groups is not supported by the evidence at hand. The suggested placement of Polylopia in the Scaphopoda extends the stratigraphic range of this group in North America back to the Middle Ordovician.