768 



NORTH AMERICAN INDEX FOSSILS. 



536. F. fusiforme Conrad. (Fig. 1120,0 and c.) Miocenic. 

 Whorls embracing to angle which bears small nodes; shoulder 



gently concave ; aperture moderately contracted. 

 Chesapeakean of Atlantic coast. 



537. F. tuberculatum Conrad. (Fig. 1120, b.) Miocenic. 



FlG. 1 1 20. a, c, Fulgur fusiforme ; d, F. tuberculatum. (Md. Survey.) 



Later whorls embracing only part way to angle ; nodes flat and 

 wide ; spirals numerous ; aperture more abruptly contracted. 

 Chesapeakean of Atlantic coast. 



538. F. maximum Conrad. (Fig. 1121, c.) 



Miocenic and Pliocenic. 



Large; young whorls tubercled, adult whorls smooth, rounded; 

 shoulder slightly concave. 



Chesapeake Miocenic of Virginia. A more slender, elongate 

 form of same character (F. rapum var., Fig. 1121, o) occurs in the 

 Caloosahatchie beds of Florida and Duplin beds of North Carolina. 



539. F. tritonis Conrad. (Fig. 1121, b.) Miocenic. 

 Earliest whorls tubercled as in F. tuberculatum, intermediate 



smooth as in F. maximum, adult whorls regularly spinose on 

 shoulder angle. 



Chesapeake Miocenic of Atlantic coast. A slender form [F. 

 rapum Conrad of another genetic series] with these characters 

 occurs in the Pliocenic of the Carolinas and Florida. 



