WHITEAVE8,] CRETACEOUS FOSSILS, NORTH WEST TERRITORY. 159 



couver Island, G. M. Dawson, 1885 : two well preserved and nearly 

 perfect but not quite adult specimens and a few fragments. 



These show clearly that the species is not an Olcostephanus of the 

 type of 0. bidichotomus, as was at first supposed, but a finely-ribbed 

 small Scaphite, very nearly related to the Scaphites cequalis of Sowerby. 

 Its ribs too are not invariably bidichotomous, for in some of the speci- 

 mens collected in 1885 they trifurcate, while in others, in closely 

 contiguous portions of the same specimen, they are bidichotomous, 

 trifurcate, or simple with shorter ones intercalated between, though 

 they are apparently never tuberculated nor nodose. 



The type of 0. Quatsinoensis is a well preserved but very imperfect 

 and immature specimen collected by Dr. Dawson in 1878 at Browning 

 Creek, Forward Inlet, where it is associated with an abundance of 

 Aucella Mosquensis, var. concentrica. 



B. FROM THE NORTH WEST TERRITORY. 



n.) From Rink Rapids, on the Lewes River, a tributary of the 

 Yukon, in latitude 60° 20' and longitude 136° 30' ; collected 

 BY Dr. G. K. Dawson in 1887. 



BRACHIOPODA. 



DiSCINA PILEOLUS. (N. Sp.) 



Plate 21, figs. 3 and 3 a. 



Upper or dorsal valve (the only one known) depi-essed conical, its 

 greatest height being a little less than one half of its maximum 

 breadth : apex erect and placed a little behind the mid-length : base 

 broadly elliptical or elliptic ovate in outline, and about one fourth 

 longer than broad. 



Surface shining, polished and marked with crowded and minute but 

 somewhat irregularly disposed concentric raised lines. 



Length of the most j^erfect specimen collected, twelve millimetres ; 

 breadth of the same, a little more than nine mm. and a half: ap- 

 proximate height, four mm. 



Two dorsal valves, one of which is nearly perfect and remarkably 

 well preserved. 



