MOIXUSCA. 703 



Turritella lorillardensis n. sp. 

 Plate LXXIX., Figs. 10-12. 



Description. The dimensions of the type specimen are: 

 height, 52 mm.; maximum diameter, 19 mm.; angle of diver- 

 gence of the sides, 27 ; number of volutions shown, 10. Suture 

 moderately impressed, situated in the bottom of an angular 

 groove; volutions moderately convex from suture to suture, 

 the lower half slightly more curved than the upper, and the 

 larger volutions flatter than those towards the apex of the shell. 

 Surface marked with fine revolving ribs, eight or nine of which 

 are of nearly equal size and are at equal distances apart; on the 

 lower half of each larger volution the first three or four inter- 

 spaces between the primary ribs are occupied by secondary ribs, 

 one or two of which in the last volution of large individuals, 

 become nearly as strong as the primary ones; at the upper and 

 lower margins of the volutions, on each of the slopes into the 

 sutural depression, there are two or three additional, smaller, 

 revolving ribs, those just below the suture being somewhat 

 more conspicuous than those above. On one individual some- 

 what larger than the type, there are upon the last volution, from 

 one to four additional raised, revolving lines in each of the inter- 

 spaces between the larger ribs. The basal margin of the last 

 volution is angular, and the lower side of the volution is flat 

 and marked with about eight or ten faint, raised, revolving 

 lines. In the internal casts the sutural cavity is narrow, indi- 

 cating a thin shell, the volutions towards the apex are convex, 

 the more mature volutions becoming more and more quad- 

 rangular in cross-section. 



Remarks; This is a common species in the Woodbury clay 

 at Lorillard. It resembles somewhat closely the T. merchant- 

 villensis', but has a less acute apical angle, and it lacks the fine, 

 -raised, revolving striae which cover the entire surface of that 

 species. 



Formation and locality. Woodbury clay, Lorillard (102), 

 near Matawan (103), Crosswicks (168). 



Geographic distribution. New Jersey. 



