314 Review of the New York Geological Reports. 



as previously remarked, to a western fossil, Orthis (striaiula?) 

 found in the blue limestone, perhaps a little more convex. Ac- 

 cording to Hall, there is a shell almost precisely similar in form, 

 but more robust, in the Delthyris shaly limestone. Fig. 7 can- 

 not be distinguished from the O. hyhrida of the Wenlock for- 

 mation of England. 



Atrypa ajffinis of a rather flatter form than the figure already 

 given under the head of Clinton group, is common at all the 

 localities of the Niagara shale. " There are probably as many 

 species of crinoidea well identified from the Niagara shale, as 

 from all the other rocks of the New York system." 



The fossil represented in figures 1 and 2 below, [Caryocrinus 

 ornatus,) is found in great numbers at Lockport, and is known 

 there by the name of the " petrified walnut." 



Plate 41, p. Ill, Hall's Report. 



Figure 3, (Cyathocrinites pyri- 

 formis.) It is supposed to be iden- 

 tical with the Cyathocrinites pyri- 

 formis of the Wenlock limestone. 



Corals occur abundantly both 

 in the shale and limestone. Those 

 in the shale are " usually referable 

 to the genera Retepora and Fe- 

 nestellaf^ those of the limestone 

 are often stone-building corals. 



