502 GEOLOGICAL SURVEY OF THE TERRITORIES. 



convex, sometimes sbowing a slight tendency to become sbouldered 

 above, last one forming about bait the entire length of the shell, gen- 

 erally a little wider abov-e, and narrowed and somewhat produced 

 below; suture well defined, in consequence of the convexity of the volu- 

 tions; aperture narrow, slightly longer than the spire, acute above, and 

 narrowing to a small, well-detined sinus at the base of the trancaled 

 columella, which is provided with two small folds, one of which is formed 

 by the twisted lower edge of the truncated columella, while the other 

 occupies a position a little above, and passes around more obliquely ; 

 surface ornamented by comparatively rather strong, regular, vertical 

 ridges or folds that sometimes become nearly or quite obsolete on the 

 bodj' volution, especially below its upper part. Crossing these folds and 

 the depressions between them, much smaller revolving ridges and fur- 

 rows may be seen on well-preserved specimens, though these are also 

 sometimes obsolescent, excepting around the lower part of the body 

 volution. 



Lengtti of a medium-sized adult specimen, 0.50 inch; breadth, 0.25 

 iucli ; angle of spire, about 42°. 



This species will be at once distinguished from the last by its projior- 

 tionally more prominent spire and less expanded body volution. It is a 

 much more abundant shell than the last, being fountl often in consider- 

 able numbers clustered together. 



Locality and ^position same as last. 



Admete? subfusiformis, Meek. 



Shell subfusiform, witli the length nearly three times the breadth; 

 spire elongated, conical, turreted ; volutions seven or eight, convex; 

 last turn more than half the entire length ; suture well detined, in con- 

 sequence of the convexity of the whorls; aperture narrow, equaling 

 about two-fifths the entire length of the shell, angular behind, and nar- 

 rowing below to a small, sharply-defined notch at the base of the trun- 

 cated columella, which seems to bear two small folds near its lower part, 

 one being formed by the twisted and truucated lower magin ; inner lip 

 a little thickened; surface ornamented by distinct, regular, vertical 

 folds that are nearly or quite obsolete on the body volution below its 

 upper part, and regular revolving lines quite well defined on the body 

 turn, especially its lower part, and appear to be obsolete on those of the 

 spire; lines of growth moderately distinct. 



Length, 0.50 inch ; breadth, 0,20 inch ; angle of spire, about 30°. 



This species differs even more strongly from the last than that form 

 does from the species rhoonhoidcs^ having a much more elevated spire and 

 a proportionally smaller body volution and ai)erture. In ornamentation 

 the three forms, however, are much alike. The species here under con- 

 sideration shows a somewhat more thickened inner lip than I have yet 

 seen in either of the others. 



For the reasons already explained, this and the last may have to take 

 the names Turricula gregaria and T. svhfusi/ormis, if all three do not, as 

 suggested further back, require to be grouped together as a new section, 

 under the names Admeiopsis rhomboides, A. gregaria, and A. suhfusiformis. 



Locality and position same as last. 



TUERITELLA COALVLLLENSIS, Meek. 



Shell attaining ? large size, elongate-conical ; volutions apparently 

 ten or more, distinctly convex, the most iirominent part of those of the 



