66 NEW YORK STATE MUSEUM 



though owing to a lack of favorable exposure they have not been 

 observed. 



The fauna of the Wiscoy is a sparse one in both species and 

 individuals. 



The following have been collected from Wiscoy creek ravine 

 and the gullies on the east side of the valley 2 to 4 miles farther 

 south : 



Manticoceras oxy Clarke Lunulicardium (Pinnopsis) wiscoy- 

 M. rhynchostoma Clarke ense Clarke 



Orthoceras sp. Paracardium doris Hall 



Pleurotomaria sp. Zaphrentis sp. 



Hyolithus neapolis Clarke Lingula ligea Hall 

 Buchiola retrostriata (v. Buck) 



Chemung group 



In discussing this division in Museum bulletin 81, 1905, (Watkins 

 and Elmira Quadrangles) the following commentary was made on 

 the general value of the term : 



The term Chemung has been applied with such a breadth of mean- 

 ing in New York stratigraphy that faunally and stratigraphically it 

 no longer meets the requirements of precise expression. The forma- 

 tion has been, in a general and vague way, regarded as that mass 

 of arenaceous deposits lying above the Portage of western New 

 York and the Ithaca of central New York, from which there is, 

 as is now known, a transition lithologically so gradual as to make 

 a separation a pure convention. In respect to fauna the " Chemung 

 group " has been commonly regarded as well defined by the pres- 

 ence of a notable series of species specially brachiopods, lamelli- 

 branchs and dictyosponges, all of which have been in a way re- 

 garded as centered about the species Spirifer disjunctus 

 and the horizon, as a whole, including a thickness of from 1000 

 to 1500 feet of strata, regarded as the horizon of Spirifer dis- 

 junctus. This conception, as we have heretofore explained, is 

 misleading, vague and inaccurate. The horizon of Spirifer 

 disjunctus follows close on the change from the Naples fauna 

 in western New York at a high altitude above the base of the 

 Portage formation. In central New York there is no such change 

 but the gradation from the Ithaca fauna out of the Hamilton fauna 

 upward into the association which carries species elsewhere con- 

 current with S p . disjunctus is very easy and it is extremely 

 difficult to draw a division plane anywhere except on the basis of 

 refined distinctions into successive faunules. Spirifer dis- 

 j unctus in this eastern region did not appear till this period 

 of "Chemung " deposition was well nigh over. For a precise use 

 of this term Chemung therefore we are thrown back on the 





