28 



in the upper part where there is an angular inflection towards the suture 

 giving an obscurely turreted form. When the shell is preserved this 

 angulation is not so apparent and the suture is indistinct or enamelled. 

 Aperture oval, somewhat effuse below, the upper half of the inner side 

 formed by the penultimate whorl, the lower half by the columella. 



Length of largest specimen seen 16 lines, width of last whorl about 12 

 lines. One small perfect specimen is in length 7 hues ; width at the aper- 

 ture 5 lines ; length of the aperture 3 lines. 



The casts of this species can always be distinguished from those of H. 

 obliqua by the obtuse shoulder-like angulation on the upper side of the 

 whorl. This in a large specimen is about two lines wide at the aperture. 

 When the shell is preserved the suture is seldom visible the surface being 

 continuous from one whorl to another. 



Locality and Formation. Trenton limestone, Ottawa ; near L'Orignal 

 and on the Island of Montreal. Black River limestone at Paquette 

 Rapids (Ottawa River). 



Collectors. Sir W. E. Logan, R. Bell, J. Richardson, E. Billings. 



HOLOPEA LAVINIA. 



Description.-^- Ovate, whorls four or five, depressed convex, the body 

 whorl large equal to about f the whole length. In the cast of the interior 

 the suture is distinct but not very deep. The apical angle is about 80 

 and in consequence of the moderate convexity of the upper whorls the 

 gpire has a somewhat smooth conical appearance only slightly notched 

 in the outline by the depressions of the sutures. 



Length about 1 inches ; width at body whorl 1 inch. 



This species is closely related to H. ovalis of the Calciferous formation. 

 The deep suture of that species gives to the cast a turreted form while in 

 this the spire is more evenly conical. 



Locality and Formation. Twenty-fifth lot in the 5th concession of the 

 township of Admaston. Trenton limestone. 



Collector. J. Richardson. 



HOLOPEA PROSERPINA. (N. sp.) 



Description. Shell very large, about four inches wide at the base and 

 apparently the same in height. Whorls about four, moderately ventricose, 

 the last one a little more than one half the whole length of the shell. Sur- 

 face with fine lines of growth of variable size, six to eight in one line. 



The specimens are all imperfect. The body whorl is very large and 

 appears to be most ventricose at the base ; above, sloping to the suture. 



