144 NEW y ORK STATE MUSEUM 



furrows ; S . murchisoni is sparse and coarse ribbed with conspicuous 

 fold and sinus, but also fimbriate; S. cymindis is smaller, having the 

 proportions but not the size of S. concinnus, 



Cyrtina rostrata Hall 



See pi i, p. 183 



These shells vary very much as do those of the Becraft Mountain Oris- 

 kany from small erect trihedral form (C. varia Clarke) to elevated shells 

 with curved cardinal area, the riblets being from 4 to 8 on each side of median 

 fold or sinus. Within these limits the shell keeps free of implication with 

 large and rugose forms which served as the type of C. rostrata Hall. 



Meristella sp. indet. 



Leptaena rhomboidalis Wilckens 



See pt r, p. 183 ; pt 2, p. 45, 1^2 



Not common. 



Leptostrophia becki Hall 



See pt 1, p. hi ; pt 2, p. 46 



The species occurs occasionally. 



Chonetes (Eodevonaria) cf. arcuata Hall 



Plate 34, figures 21-31 



See Hall. Palaeontology of New York. 4:119, pi. 20, fig. 7 



Professor Hall described from the Onondaga limestone a large Cho- 

 netes, C. arcuata, having a highly convex ventral valve, specially arched 

 in the urhbonal region, a surface covered with fine striae and with the hinge 

 denticulations which characterize Eodevonaria fully developed. There is a 

 closely allied shell in this fauna notable for its conspicuous size and its finely 

 striated exterior surface, but it is a flat, relatively elongate shell, not pre- 

 senting the arched surface nor the median ventral depression which charac- 

 terize C. arcuata. The legitimate ancestor of that species it may well 

 be but its differences are recognizable and are expressed in the accompany- 

 ing figures. Among other species of Eodevonaria, Chonetes dilatata 

 Roemer (Coblentzian) possesses its outline and flatness and is a close ally. 



Chonetes highlandensis now 



Plate 34, figures 32-41 



There is a group of small highly convex coarsely ribbed Chonetes which 

 are as characteristic of early Devonic age as those which constitute the sub- 



