122 



at the sides ; the sixth, seventh and eighth are also gently convex, hut 

 more or less angular or subcarinated a little below the middle. The 

 body whorl is moderately inflated and faintly and spirally subcarinated 

 considerably above the middle, and there is sometimes a second and 

 smaller keel or ridge below the first. Tho aperture appears to have 

 been obliquely subovate when perfect, and to have contracted suddenly 

 below into a short, nearly straight, and channelled beak. 



The surface is transversely ribbed and striated, and the lower whorls 

 are also encircled by narrow, linear, revolving ridges. A large portion 

 of the test ad the body whorl happens to have been broken off in the 

 few specimens yet collected, but on the last whorl but one the transverse 

 ribs are distant, narrow and flexuous. On this whorl, too, and on that 

 which precedes it, there are three rather widely separated revolving 

 ridges above the angle, and four much more closely disposed ones below 

 it. The summit of the angle also bears a single spiral ridge, which 

 gives the shell a lightly carinated aspect, but the ridge on the angle is 

 not larger nor more prominent than either of those above it. All the 

 revolving ridges are marked by tubercles where the ribs cross them, but 

 the tubercles are largest on the angles of the whorls. 



Middle Shales, Division D, of the north-west side of Hornby Island, 

 three specimens; also Productive Coal Measures, Division A, at Nanaimo 

 Eiver, V, I., two miles and a-half up, two or three imperfect examples; 

 J. Eichardson, 1811 and 18T2. 



The spiral keel is not very distinctly defined in any of the specimens, 

 and in some it is almost obsolete. 



This shell is pi'obably nothing more than a local variety of P. tenuis, 

 which may usually be distinguished from the typical form by its slender 

 and more elongated shape, more evenly rounded whorls, and by the 

 numerous elevated revolving ridges on the two last volutions. The 

 two forms, however, seem to be connected by intermediate gradations 

 both of shape and sculpture. 



Cerithium Lallierianum, D'Orbigny. Variety StrciENSE. 



Plate 15, figures 10 and 10a. 



Cerithium Lallierianum, D^Orbigny. — Pal. Franc, Terr. Cret., Vol. II., p. 365, Atlas, 



pi. 229, figs. 7-9. 

 " " Forbes. — Quart. Journ. Geol. Soc. Lond., Vol. I., p. 352, 



pi. 4, fig. 10. 



Sucia Islands, in Division A., six well preserved examples ; also Pro- 



