233 



and obscure, situated just below the middle of the whorl. The surface is 

 in general smooth, but in perfect specimens obscurely marked by fine 

 striae, curving backwards to the band. 



Length from 18 to 30 lines ; diameter of last whorl from 6 to 8 lines. 



This species is closely allied to M. gracilis (Hall), but differs in the 

 position of the band, and in the form of the aperture. In the Trenton 

 species, the band is in the middle of the whorl, and the lip is continuous 

 all round the inner side of the aperture. 



M. Vesta has the whorls less convex. 



Locality and Formation. — H, I, K, L, M, N, Table Head and Point 

 Rich, Newfoundland ; Quebec group. 



Collector. — J. Richardson. 



MUIICIIISONIA OlCELIA. (N. Sp.) 

 Fig. 219. 



Description. — Shell rather small and slender ; spire of from ten to 

 fifteen whorls, which are strongly and sharply angular at about the lower 

 third, with a straight slope to the suture above. Space between each two 

 carinas angular, not concave as in M. Catharina. Surface unknown 

 Apical angle from 15*^ to 20°. 



This species belongs to the same group with M. perangulata (Hall) of 

 the Black River and Trenton, from which it is distinguished by its 

 elongated and slender form. It is also allied to M. Ustella of the Guelph 

 limestone, see p. 155, ante. 



Length about 12 lines ; width of last whorl about 3^ lines. 



Locality and Formation. — L, Table Head and Point Rich, Newfound- 

 land ; Quebec group. 



Collector. — J. Richardson. 



MUKCHISONIA SORORCULA. (N. Sp.) 

 Pig. 220. 



Description. — Shell turbinate, with about five acutely angular whorls ; 

 apical angle from 55'^ to GS'' ; base strongly convex. The whorls are 

 strongly angular along the middle, above gently concave to the suture ; the 

 band situated on the edge of the angulation. The body-whorl below the 

 angle has a single carina, between which and the margin there is a 

 concave band, usually a little more than half the width of the upper side 

 of the whorl. Aperture angular on the outside, rounded on the inner 

 side, partly formed by the penultimate whorl, the lower-inner lip 



Q 



