170 Silurian Fossils of Canada* 



wliorl would be elongate sub-oval (or owing to the indentation 

 caused by tlie preceding wliorl, reniform) in the proportion of 

 about two and a half to five. 



Allied to B. rotundatiis, (Hall) but that species according to the 

 figures has the umbilicus full half the whole diameter, and the 

 whorl angulated at the sides. In this species the umbilicus is 

 about one fourth the whole diameter, and the whorls rounded at 

 the sides. The aperture also in B. Charon must be proportionally 

 much wider. 



There appears to be some variation in the proportions of dif- 

 ferent individuals of this species, but as most of the specimens are 

 mere fragments, the amount cannot be determined at present. 



Locality and Formation. — Pauquettes Rapids, Black River, 

 and Birdseye Limestone. 



Collector, — Sir W. E. Logan. 



Genus Piloceras (Salter.) 

 PiLOCERAS (Salter) Quart. Jour. Geo. Soc. vol. 15, p. 376. 1859. 



This genus consists of short, thick, curved Orthoceratites, with 

 a very large siphuncle, the smaller extremity of which is, for a 

 short distance, filled with a solid secretion so organised as to exhi- 

 bit the appearance of several hollow cones inserted one within 

 another. 



The specimens upon which Mr. Salter founded the genus were 

 imperfect and did not exhibit the true septa, but there are now 

 in the collection of the Greological Survey of Canada two frag- 

 ments of difibrent individuals of a species of this genus, with 

 several of the septa well preserved, so that there can be no doubt 

 of their existence. The discovery of these fossils, and also of 

 Maclurea Atlantica in Canada, furnish an interesting additional 

 proof of the value of organic remains in establishing the equiva- 

 lency of widely separated deposits of rock. When Sir R. I. Mur- 

 chison, in 1857, announced that certain beds of limestone in 

 Scotland were of the age of the Calciferous Sandrock and Chazy 

 formations of Canada and New York, the only evidence consisted 

 of a few imperfect fossils, among which were an Ophileta, consi- 

 dered by Mr. Salter to be either identical with or closely allied to 

 the Canadian 0. compacta, together with a Maclurea of a new 

 species and several Orthocerites, resembling in aspect those asso- 



