770 NORTH AMERICAN INDEX FOSSILS. 



Chesapeakean formation of the Atlantic coast. 



543. S. canaliculatus (Linn.). Pliocenic-Recent. 

 Young whorls nodulated, adult with more or less strongly 



developed carina. 



Pliocenic of the Carolinas; Pleistocenic and Recent, Cape Cod 

 to Gulf of Mexico. 



544. S. pyriformis (Conrad). Miocenic. 

 Young whorls tubercled, later keeled ; adult with rounded whorls. 



Fig. 1 1 22. Sycoiypus rugosusy X %- (Md. Survey.) 



Miocenic of North Carolina. In 5\ pyrus of the modern fauna 

 the rounded outer lip begins early, the curvature being continuous 

 from the sutural canal. 



545. S. excavatus Conrad. (Fig. 1 121, e.) Miocenic-Pliocenic. 

 Differs from the preceding in having the outer lip of last whorl 



continuous without shoulder angle, and with sharp posterior notch. 

 Duplin beds of Carolinas. 



CLVII. Strepsidura Swainson. 

 Like Fulgur but with short, curved canal, higher spire, and 

 whorls often ribbed. Eocenic-Miocenic. 



546. S. subscalarina Heilprin. (Fig. 1123, a-c.) Eocenic. 

 Primitive varieties (Fig. 1123, a) high-spired; whorls rounded 



or subangular, and ribbed, specialized varieties (Figs. 1123, c, b) 



