MOLLUSCA. 697 



1905. Turritella granulicosta Johns., Proc. Acad. Nat. Sci. 



Phil. (1905), p. 21. 

 1892. Turritella compacta -Whitf., Pal. N. J., vol. 2 (Monog. 



U. S. G. S., vol. 18), p. 142, pi. 18, figs. 8-9, 

 1905. Turritella compacta Johns., Proc. Acad. Nat. Sci. Phil. 



(1905), p. 21. 



Description. "Shell small, with very short, slender, and 

 closely coiled but rapidly enlarging whorls, giving 1 a rapidly in- 

 creasing diameter to the shell with increased growth. Apical 

 angle about 15. Volutions about eight in number in a speci- 

 men which has been not more than seven-eighths of an inch in 

 its extreme length; flattened convex on their outer surface, and 

 subangular at the upper and lower margins, with a nearly flat 

 base. Lower margin of the volution proportionally larger than 

 the upper. Suture lines between the whorls narrow, but very 

 distinctly marked. Surface marked by about 12 fine, thread- 

 like revolving ribs, three of which are larger than the rest, are 

 placed at equal distances from each other, and from the upper and 

 lower edges, and are slightly undulated so as to produce a series 

 of minute nodes. This character shows itself to a much less 

 extent on some of the smaller ribs. Under surface of the body 

 volution marked by a few fine revolving ribs, with regular con- 

 cavities between them." (Whitfield.) 



Remarks. The type of this species has the shell preserved on 

 one side only, the opposite side showing the characters of the 

 internal cast. A comparison of this specimen with that used by 

 Whitfield as the type of his T. compacta shows the two to be 

 essentially the same, so that T. compacta becomes a synonym. 

 The species has not been met with in the recent collections of the 

 Survey, so that its proper horizon cannot be certainly determined, 

 but from the lithologic characters of the type the species appar- 

 ently belongs in the Navesink fauna, although it is possibly from 

 the Merchantville. 



Formation and locality. ? Navesink marl, Burlington County 

 (Gabb). 



Geographic distribution. New Jersey. 



