New Species of Fossils. 205 



loose in this vicinity by Mr. I). B. Lowling in 1888,) 

 also on the shores and islands of Cedar Lake and on the 

 Saskatchewan below Cedar Lake by Mr. J. B. Tyrrell in 

 1890. At eaeb of the-^e localities it is apparently abundant 

 and often associated with IsochiUna grant lis, Jones. 



The specimens consist cither of natural moulds of the 

 exterior of the shell or of casts of the interior, in a 

 compact fine grained dolomite, and in no case is there any 

 vestige of the actual test remaining. In several of these 

 natural moulds, however, the minutest details of the sur- 

 face ornamentation are well preserved, and it is from wax 

 impressions made from two of these moulds that the figures 

 on Plate HI. were drawn. 



The species is apparently most nearly related to the 

 Strophomena Ledd of Billings, ' from division 3 of the Anti- 

 costi group of the Island of Anticosti, (which Mr. Billings 

 correlates with the Llandovery of England and with the 

 Clinton of tho State of New York), but seems to differ 

 therefrom in its much' larger size, and in the greater pro- 

 portionate length of its cardinal spines. Both it and S. 

 Leda are evidently what Professor H. L. Williams' would 

 call "geological mutations " of the "race which began in 

 Strophomena altanata'm the Trenton stage," but they form 

 a marked exception to his statement that in the American 

 race of tho S. alternata type the slender mucronate points 

 at the terminations of the hinge line " first appear in the 

 Tully limestone." 



Pentamerus decussatus. (Sp. nov.) 



Plate iii, figs- 3 and 4. 



Shell large, usually longitudinally and rather narrowly 

 subovate, about one third longer than broad, and broadest 

 a little in advance of the midlength, but sometimes nearly 



1 Geol. Surv. Can., Palasoz. Foss., vol. 1, 1865, p. 120, figs. 08 and 99. 



2 See his paper on " The Cuboides Zone, and its Fauna," in Bull, (icol. Soo. 

 America, published May, 1890. 



