f 



240 NEW YORK STATE MUSEUM 



for identification. Professor Hall^ calls attention to these peculiar 

 coproliticlike nodules in the rocks of this formation in Albany 

 county, N. Y. Our specimens agree with his in that they are 

 '' uniformly elongate or oval in form." ? 



Orbiculoidea ampla Hall 

 Rare in the lower Oriskany where alone it was found. 



0. jervisensis (Barrett) 



The most characteristic shell of the middle Oriskany. It occurs 



rather less abundantly in the Lower Oriskany. A noticeable feature 



of this species is that it frequently lies at right angles to the bedding 



plane. 



Pholidops ovata Hall 



This little shell is quite abundant on the weathered rock surfaces 

 of the Upper Coeymans. It is also present in the Lower New Scot- 

 land. A specimen of average size measures 3.5mm by 3mm. 



Leptostrophia oriskania Clarke 

 Only one specimen was found and that in the Lower Oriskany. It 

 is smaller than the average given by Clarke^ having a length of but 

 12mm and a width of 14mm. The irregular, concentric wrinkles 

 can be plainly seen. 



Leptaena rhomboidalis (Wilckens) 

 Abundant in the whole of the Helderbergian and Lower Oriskany. 

 The characters of the shell are very constant and hold true to the 

 type. It is specially abundant in the New^ Scotland and Becraft. 



Stropheodonta becki Hall 

 Quite abundant in the whole of the Helderbergian, occurring also 

 in the Upper Oriskanian. It holds quite true to the type description. 



S. varistriata (Conrad) 

 Very abundant in the Lower and Upper Manlius, it is also present 

 in the Favosites bed and Coeymans. The Coeymans species differs 



"Pal. N. Y. 1859. 3:158. 



'N. Y. State Mus. Mem.3, p.53, pi.;, fig.29-35. 



