704 CRETACEOUS PALEONTOLOGY. 



Turritella merchantvillensis n. sp. 

 Plate LXXIX., Fig. 13. 



Description. — The dimensions of a specimen incomplete at 

 each extremity are: heigfht, 60 mm.; maximum diameter, 17 

 mm. ; angle of divergence of the sides about 10° ; number of volu- 

 tions shown, 9. If the specimen were complete at the apical 

 extremity, it would be 75 mm. or more in length, with about 15 ■ 

 volutions. Suture moderately impressed, situated in the bottom 

 O'f an angular groove; the surface of the volutions moderately 

 convex from suture to suture, the greatest diameter below the 

 middle so' that the slope of the lower half is more abrupt than 

 that of the upper. Surface of the shell marked with 10 or 12 

 fine, raised, revolving costae, one of which, near the base of the 

 volutions, is slightly stronger than the others ; between the costae 

 the surface is entirely covered with much finer, raised, revolving 

 lines. The internal casts have a narrow, almost closed sutural 

 cavity, indicating a thin shell, and they usually have a more or 

 less indistinct, narrow, revolving band above the middle of the 

 volutions ; surface of the volutions moderately convex, sometimes 

 tending to^ become more flattened in the more mature portions 

 of the shell. 



Remarks. — This is the abundant species of the Merchantville 

 clay-marl, and usually occurs in the form of internal casts, 

 although impressions of the exterior are frequently preserved in 

 the matrix. The species, resembles T. lorillardensis, but it is 

 more slender, with a more acute angle of divergence, and the 

 surface markings of the two species are different, the surface of 

 T. merchantvillensis being entirely covered with extremely fine, 

 raised, revolving lines between the stronger costje. 



Formation, and locality. — Merchantville clay-marl, near Mat- 

 awan (100*, loi), near Jamesburg (139, 140, 141), Lenola 

 (163), Merchantville (162). 



Geographic distribution. — New Jersey. 



