WHITEAVE8,] DEVONIAN FOSSILS OP MANITOBA, ETC. 281 



From that species they appear to differ principally in their much more 

 slender branches and dissepiments, more hexagonal fenestrules, and in the 

 greater extent to which the arrangement of the zowcia in two rows pre- 

 vails. 



BRACHIOPODA. 



(S.) DisciNA. (Sp. Indet.) 



Western shore of Dawson Bay, at the first small point north of the 

 mouth of the Red Deer River, D. B. Dowling, 1889 ; two casts of tlie 

 upper valve, which are too badly preserved to admit of determination or 

 accurate description. Both are small and nearly circular in basal outline, 

 with a depressed apex, which is nearly central in one of the specimens 

 and slightly excentric in the other. 



Chonetes Logani, var. Aurora, Hall. 



Oh-onetes Lof/ani, var Aurora, Kail. Pal. St. N. York, vol. IV, pt, 1, p. 13T, pi. 

 xxii, tigs. 16-28. 



Williams. 1880. Bull. Geol. Surv. Am., vol., I, pp. 

 490 and 491, pi. xii, iigs. 10 and 11. 

 " " " Whiteaves. 1891. This volume, p. 21.3, pi. xxix, figs. 



2 and 2a. 



Red Deer River, half a mile above the Lower Salt Spring, J. B. Tyrrell, 

 1889 : abundant. 



Chonetes Manitobensis. (N. Sp.) 



Plate SI, figs. 1,1a and 2. 



Shell small, concavo-convex, strongly compressed, transversely semiel- 

 liptical, about twice as broad as long and broadest at the hinge line : car- 

 dinal extremities angular and very slightly produced : sides rounded in 

 front : anterior margin nearly straight or but faintly convex in the centre. 

 Ventral valve compressed convex, its cardinal border armed on each side 

 of the beak with 'three or four slender and widely divaricating spines, 

 which increase in length outward : its beak inconspicuous, minute and not 

 projecting, its hinge area narrow, with a small triangular fissure. Dorsal 

 valve shallowly concave, its beak minute and its hinge area narrower than 

 that of the ventral. 



Surface marked with very minute radiating raised lines, which increase 

 in number at variable distances from the beaks, by bifurcation, trifuroation 

 or intercalation, so that around the outer margin as many as from seventy 



