GUELPH FAUNA IN THE STATE OF NEW YORK 41 



ridges to the anterior margin. In size this form rivals M. durhamensis 

 Whiteaves, which however is readily distinguished by its extremely large 

 and prominent beaks in both valves. In some features the species is still 

 more closely related to M. walmstedti Dav. & King than to M. prisca. 

 Monomerella walmstedti is a species from the corresponding beds 

 of Gothland, which has a similar development of the umbo and cardinal 

 region, but possesses a more convex umbo m the pedicle valve. Davidson 

 points out the close relationship of that species with M. prisca. Mono- 

 merella noveboracum shows relationship also, in the character 

 of its brachial valve, with M. kingi Hall & Clarke, from the Niagaran 

 dolomites of Hawthorne 111.' This Shelby species is the only representa- 

 tive of the family Trimerellidae yet found in the State of New York. 



DALMANXXLA Hall & Clarke. 1892 

 Dalmanella cf. elegantula Dalman (sp.) 



Plate 4, fig. 9 



For synonomy of Orthis elegantula see Hall & Clarke, Paleontology of New 

 York. 1892. v. 8, pt i, p. 207, and Davidson, Monogr. British Silurian 

 Brachiopoda. 



Some small and incomplete specimens of immature individuals found 

 at Rochester and in the upper Guelph at Shelby suggest affinity with the 

 specific type of Dalmanella elegantula in the relative convexity 

 of the two valves and the character of the surface sculpture so far as 

 retained. 



The presence of casts of the interior of two species of Orthis in the 

 Guelph of Ontario is mentioned by Whiteaves ; and it is also cited from 

 the Guelph beds at Cedarburg Wis. a 



1 See Pal. N. Y. v. 8, pt i, pi. 40, fig. 2. 

 "Geol. Wisconsin, 2:379. 



