MOLLUSCA. 705 



Turritella marshalltownensis n. sp. 

 Plate LXXIX., Fig. 14. 



Description. The dimensions of a specimen incomplete at 

 each extremity and slightly compressed are : height, 60 mm. ; 

 maximum diameter, about 20 mm.; angle of divergence of the 

 sides, about 12, number of volutions shown, 7. If the speci- 

 men were complete to the apical extremity it would be 75 mm. 

 or more in length, with 15 or more volutions. Suture moder- 

 ately impressed, situated in the bottom of a broadly angular, re- 

 volving groove; the surface of the volutions moderately convex, 

 their greatest diameter at or a little below the mid-height. Sur- 

 face marked by about 12 fine, revolving costse, between which, in 

 the lower half of the volution at least, there are usually alternate 

 smaller ones. Shell substance thin. 



Remarks. This species most closely resembles T. merchant- 

 villensis, but the greatest diameter of the volutions is higher 

 than in that species, the stronger revolving costae are slightly 

 broader and flatter, and the entire surface is not covered by the 

 very fine revolving lines of that species. This species occurs 

 abundantly in the Marshalltown clay-marl near Swedesboro, with 

 the shell substance well preserved, but the specimens are almost 

 always somewhat compressed, doubtless because of the thin- 

 ness of the shell, and they are always incomplete, neither the 

 apex nor the perfect aperture having been observed in any speci- 

 men. 



Formation and locality. Marshalltown clay-marl, near 

 Swedesboro (177). 



Geographic distribution. New Jersey. 



Family VERMETIDAE. 

 Genus SILIQUARIA Bruguiere. 



Siliquaria pauperata Whitfield. 

 Plate LXXIX., Figs. 18-20. 



1892. Siliquaria pauperata Whitf., Pal. N. J., vol 2 (Monog. 

 U. S. G. S., vol. 1 8), p. 149, pi. 1 8, figs. 26-28. 

 45 PA ^ 



