766 CRETACEOUS PALEONTOLOGY. 



selves preserved this would be an easy means of identifying the 

 two genera, but in these internal casts the folds are often very 

 faintly shown. All the specimens of the species under discussion, 

 however, which have been observed, have indications of these 

 vertical folds, and they were also mentioned in the original de- 

 scription of the species by Gabb. Consequently the species is here 

 placed in the genus Odontofusus. 



Formation and locality. Navesink marl, near Crawfords Cor- 

 ner (i26 7 ), Middletown (ii3 2 ), Crosswicks Creek (195), Free- 

 hold, Holmdel (Whitfield). 



Geographic distribution. New Jersey. 



Odontofusus slack! (Gabb). 

 Plate XC, Fig. 17. 



1861. Fasciolaria Slackii Gabb, Proc. Acad. Nat. Sci. PhiL 



(1861), p. 322. 

 1864. Fasciolaria Slackii Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 21. 



1868. Fasciolaria Slackii Con., Cook's Geol. N. J., p. 730. 

 1876. Fasciolaria Slackii Gabb, Proc. Acad. Nat. Sci. Phil. 



(1876), p. 282. 

 1892. Odontofusus Slacki Whitf., Pal. N. J., vol. 2 (Monog. 



U. S. G. S., vol. 18), p. 66, pi. 6, figs. 8-9. 

 1905. Odontofusus slackii Johns., Proc. Acad. Nat. Sci. PhiL 



(1905), p. 24. 



Description. "Shell, as shown by internal casts, slender, 

 fusiform, nearly of equal length above and below the point of 

 greatest diameter of the body whorl ; spire slender, apical angle 

 about 35 to 40; volutions five or six (none of the specimens 

 are perfect to the apex) ; angular in the middle and slightly 

 convex above^and below, the last one increasing more rapidly 

 than those above; sutures distinct and deep; anterior end pro- 

 longed into a straight, moderately slender canal; columella 

 strong, marked by a single oblique, well defined ridge or fold 

 at about the middle or above the middle of its length; aperture 



