62 COXTRIBUTIONS TO CANADIAN PALiEONTOLOGT. 



in section A, on j)age 9. It, however, was first dLscovered on the Second 

 or Xorth Branch of the Milk Eiver, in IST-t, by G. M. Dawson, as 

 stated in his British North American Boundary Eeport, in rocks 

 which he has since designated as the St. Mary Eiver Series. 



It is doubtful whether this Splvvrium should be regarded as merely 

 a local variety of the *S'. forinosmn, or as a distinct species. As compared 

 with Meek's description of S. fonnosum. the specimens collected bv Br. 

 Dawson and Mr. "Weston are not nearly so much pointed at the poste- 

 rior end of the ba^e, nor so obliquely truncated posteriorly, and the 

 cardinal margin, in the Canadian sjDecimens, is more nearl}- jjarallel 

 with the ventral. 



]\LvcTRA (Ct^ibopiiora) alta, Meek and Hayden. 



Xuctra oltii, ^Meek and Hayden. 1S5G. Proc. Ac. Xat. Sc. Phil., vol- A'III.,p. 271. 

 M,ii-tra(Ojm'bophom)nlta,Me.e]^. 1876. Rep. U. S. Geol. Surv. Terr., vol. IX., p. 

 210, pi. 37, figs. 2, a, b. 



Milk Eiver Eidge, E. G. McConnell, 1SS2 : hve or six large single 

 valves. 



CoRBULA scBTRiGONALis, Meek and Hayden. 



Corhvla whtrigonaliK, iMeek and Hayden. 1856. Proc. Ac. Nat. Sc, Phil., vol. 

 VIII, p. 110. 



Corhitl" (Potamomiin) suhlrigonalix, Meek and Hayden. 1860. lb., vol. XII., p. 432. 



Corl'ula sithtriijoniilix,^leek.lS76. Eep. U. .S. Geol. Surv. Terr., vol. IX., p. 52fi, 



pi. 40, figs. 3, a, b. Illustrated als(_i (in pi 19, 

 figs. 10-17, of Dr. C. A. "White's Eev. Non- 

 Marine Foss. Moll. N. Am. 



Peigan Creek, Township 7, Eange 6, west of 4th Princi]3al Meridian, 

 E. G. McConnell, 1883 : a small piece of rock containino- a few de- 

 tached valves of this species. 



CoRBULA PERUNDATA, Meek and Hayden. 



Corhiila pcrmvlala, :\ree)c and Havden. 1856. Proc. Ac. Nat 8c Phil vol VIII 

 p. 116. • ■, • 



" Meek. 1876. Eep. U. S. Geol Surv. Terr., vol. IX., p. 530. pi. 

 40, figs. 4 a, b, c, d. 



With the preceding, of which, as already remarked on page 9, Dr. C. 

 A. White thinks it only a variety ;— also near theU. S. Boundary line, 

 on a branch of the east fork of the Milk Eiver; at both places collected 

 by E. G. McConnell in 1883. 



