7 82 



NORTH AMERICAN INDEX FOSSILS. 



tinct shoulder occurs irr some species, 

 with the ribs noded on the angle. The 

 last whorl generally smooth, but may 

 retain the ribs and nodes as irregular 

 folds. Oligocenic-Recent. 



571. T. wilsoni Conrad. (Fig. 1142.) 

 Oligocenic-Miocenic. 



Differs from the next species in 

 its smooth, somewhat subcylindrical, 

 or flattened last whorl, in the number 

 of ribbed young whorls (7 or more) ; 

 concave shoulder, rather steeply in- 

 clined, angle rounded and faintly and 

 bluntly nodulated; faint spirals on 

 lower part of body whorl. 



Vicksburgian of Mississippi ; Alum 

 Bluff beds of Florida. 



572. T. chipolana Dall. (Fig. 1 143.) 

 Oligocenic-Miocenic. 



Young whorls (two or three) with 

 coarse ribs which become obsolete 

 later on; last whorl round; interca- 

 lated spirals between the strong pri- 

 mary ones; columella with three 

 oblique folds; protoconch cylindrical, 

 of many whorls. 

 Chipolan and Alum Bluff beds of Florida. 



Fig. 1 142. Turbinella ivilsoni. 

 (After Conrad.) 



CLXXV. Vasum Link. (Cynodonta Schum.) 

 Like Turbinella but with flat or concave shoulder and angle 

 with strong, coarse and flat spines ; one or more additional rows 

 of spines on the lower part of whorl. Oligocenic-Recent. 

 573. V. haitense Sowerby. (Fig. 1144.) Oligocenic-Miocenic. 

 Spire high, acute, of flat-ribbed whorls, rapidly broadening out 

 in last 2 or 3 whorls which have concave shoulder and strong, 

 triangular, compressed spines; a second row of smaller, sharp 

 spines near base; spirals faint. The variety engonatum (Dall) 

 has more spines and less elevated and Jess acute young spire. 



