236 



NORTH AMERICAN INDEX FOSSILS. 



121. C. vicinus (Castelnau). (Fig. 287.) Devonic. 



Shelly ±*inch in^width, strongly convex. Cardinal margins 



deflected when seen from the convex side. Striae finer and more 



closely crowded than in C. mucro- 

 natus. Spines short and oblique. 



Hamilton of New York, Ohio, 

 Wisconsin, Nevada. 





jpk 1 1 





122. C. coronatus (Conrad). (Fig. 

 288.) Devonic. 



Large (about y 2 inch in width), 

 moderately convex, with numerous 

 surface striae and 5 or 6 oblique 

 spines on each side of the beak. 

 Interior of pedicle valve strongly pus- 

 tulose outside the wide spreading ad- 

 ductor impressions. 

 Hamilton of New York, Pennsylvania, Illinois, Wisconsin, 

 Ontario. 



123. C. pusillus Hall, (Fig. 285, c-d.) Devonic. 



Small (about y 2 inch wide) with somewhat convex pedicle valve ; 



djgfeta 



Fig. 287. Chonetes vicinus, 

 with enlargement of interior qf bra- 

 chial valve. (After Hall.) 





Fig. 288. •'_" Chonetes coronatus T_ (After Hall.) 



its umbo abruptly incurved at the hinge extremities which are 

 usually obtuse. Brachial valve nearly as concave as the pedicle is 

 convex. Striae but little elevated. 



Hamilton of Illinois, British America. 



