1898] Whiteaves — On SOME Fossil Cephalopoda. 119 



intermediate longitudinal ridges characteristic of that species. 

 Both clearly belong to Barrande's " Group 6 " of the genus 

 Orthoceras and to Hyatt's genus Dawsonoceras* The surface 

 ornamentation of O. Beauportense appears to be decidedly dif- 

 ferent from that of any of the small annulated species of 

 Orthoceras from the Trenton limestone of the State of New York 

 described and figured by Hall in the first volume of the Palaeon- 

 tology of that State. O. bilineatuni. Hall, is a much larger and 

 more robust species, with coarser annulations and two series of 

 longitudinal ridges or linear elevations. In O. clathratuin, 

 Hall, the longitudinal markings are very minute and crowded, 

 and are said to consist of " sharp elevated lines distant ^^ of an 

 inch," or very little more than a half a millimetre apart. There 

 are, also, no comparatively coarse and distant longitudinal ribs 

 or ridges in O. textile, Hall, and in that species the transverse 

 annulations are represented as both prominent and angular. 



Tripteroceras Lambil 



Gonioceras Lambi, Whiteaves. 1891. Trans. Royal Soc. Canada, 



Vol. lx, sect. 4, p. 86, pi. Xl, figs. i,and i a-b. 



Triptoceras Lambi, Clarke 1897. Geol. Minnesota, Final Rep., 



Vol. Ill, pt. 2, p. 793, pi. 56, figs. I and 2. 



Tfipteroceran Lambii, Whiteaves. 1897. Geol. Surv. Canada, 



Palseoz. Fossils, vol. Ill, pt. 3, p. 213. 



The type of this species is a well preserved specimen of the 

 septate portion of the shell, rather more than ten inches in length 

 but imperfect at both ends, collected in the Galena — Trenton 

 limestone at East Selkirk, Manitoba, by Mr. J. B. Tyrrell in 1890. 

 Until quite recently, the only other specimen that the writer had 

 seen is the badly preserved but otherwise similar cast collected 

 at Wekusko Lake, in the District of Saskatchewan, by Mr. 

 Tyrrell in 1897 and referred to on page 2 14 of the third volume of 

 " Palaeozoic Fossils " published by the Geological Survey of 



*It seems to the writer that it would be more euphonious and more in accor- 

 dance with classical usage to write Dawsoniceras an.i Bai'raniHceras rather than 

 Dawsonoceras, and Barrandeoceras. 



