252 



Camarot(kchia Ekwanensis, Whiteaves. 



Plate 25, figs. 4, 4 a, and 4 6. 



Camarotocfeio £i«;ancn,ii,'s, Whiteaves 1904. Geol. Surv. Canada, Ann. Rep., vol. 



XIV, pt. F, p. 42. 



" Shell small, moderately convex, transversely subelliptical and wider 

 than long. 



" Ventral valve with an extremely small, narrow, erect or straight 

 beak, behind ; and a well defined mesial sinus, that extends backward to 

 about the midlength in front; the whole surface of the valve marked with 

 thirteen rather distant, angular radiating ribs, three in the mesial sinus 

 and five on each side 



" Dorsal valve with a still smaller beak, and with a fold corresponding 

 to the mesial sinus of the ventral, its surface marked with twelve angular 

 ribs, four on the fold and four on each side of it. 



" Hinge area and interior of the valves unknown. 



" Portage road at falls : one well preserved cast of the interior of the 

 closed valves. 



This small rhynchonelloid may possibly prove to be an extreme variety 

 of C. neglecta (the Atrypa neglecta. Hall, of the second volume of the 

 Palaeontology of the State of New York) from which it seems to differ 

 chiefly in its transversely and rather narrowly subelliptical marginal 

 outline. 



Ateypa eeticularis, L. 

 Foot of portage road : two small specimens. 



Glassia variabilis 1 Var. 



Plate 26, figs. 6, 6 a, and 6 h. 



Cfr. Glassia variabilis, Whiteaves .1904. Geol. Surv. Canada, Ann. Rep., vol 



XIV, pt. F, p. 42. 



Foot of portage road : one specimen, that is doubtfully referred to this 



species. It does not show any vestige of the spiralia or of any of the 



other characters of the interior of the shell. It is perhaps a little more 



convex than the typical form from the Winisk River, and the sinus in its 



ventral valve seems to be a little deeper proportionately. In these 



respects the specimens from the Ekwan and Fawn rivers are more like 



the Atrypa subovata of Sowerby, and those from the Winisk are more like 



the A. compressa of the same author, both of which are now regarded as 



forms of Glassia subovata. The original description of G. variabilis is 



reprinted on page 273, and the typical form of the species is illustrated on 



Plate 26, figs. 3, 4 and 5. 



