MARYLAND AND WEST VIRGINIA ORISKANY 315 



On analyzing this Cumberland fauna, it is seen that of the 58 species 

 found there, 25 are restricted and do not occur to the north in New York. 

 Of the remaining 33 species, 10 are also found in the Helderbergian, 

 a far greater number than in the Upper Oriskany of New York, where 

 but 2 species are common to it and the Helderbergian ; 19 are also found 

 elsewhere in the Lower Oriskany and 25 in the Upper Oriskany. The 

 degree of evolution therefore indicates that the Cumberland fauna is older 

 than that of the typical Upper Oriskany of New York, but not quite as 

 old as that of the Lower Oriskany of Becraft mountain. 



If this fauna were derived from a limited zone, its developmental 

 progression would indicate that the Cumberland Oriskan}^ is older than 

 the Hipparionyx fauna of New York and not quite as old as that of 

 Becraft mountain. However, it is certain that the Helderbergian here 

 passes without break into the Oriskany, as can be seen at *' Devils Back- 

 bone," near Cumberland, and it may be that both the Lower and Upper 

 Oriskany are there present. It is probable that Mr Andrews" collection 

 was derived from the entire series, and that there is some mixing. This 

 causes the Cumberland Oriskany to appear older than the Hipparionyx 

 fauna, when it probably contains both the latter and the Becraft fauna. 



The following species are from Ke}'ser, Mineral county, West Virginia, 

 and were obtained on the north branch of the Potomac river : 



Spirifer arenosus (Conrad). 16674,16676. Bcachia suessana Hall. 16679. 

 Spirifer murchisoni Castelnau. 16675. Slropheodonta magnified Hall. 16673. 

 Eatonia pecidiaris (Conrad). 16678. JDiaphorostoma ventricosa (Conrad). 16673. 



Moorefield, Hardy county, West Virginia : 



Spirifer arenosus (Conrad). 28104. 



The following forms are from Pendleton county, West Virginia, and 

 were collected on the north fork of south branch of Potomac river: 



OrlJiis {Bhipidomella) muscidosa Hall. Spirifer mu rcliisoni Castelnau. 28100. 



18156,18157. Spirifer Cumberland) % Hall? 28101. 



Stropheodonia magnifica Hall. 18154. Camaroicechia barrandei H&U. 18159. 



Slropheodonta lincklssni Hall. 28112. Meristella la la Hall. 28092,28093. 



Hipparionyx pr oximus V&imxem. 18155. Anoplotheca flabellites (Conrad). 18160. 



Chonostrophia complanaiaH&U. 18153. Jiensseheria sp. undet. 18162. 



Spirifer arenosus (Conrad). 18158. ]tensseheriamarylandica~Ha.]}. 18161. 



Spirifer like arenosus in form, but with- Diaphorosloma ventricosa (Conrad). 18164. 



out a plicated fold and sinus. 28106. Platyceras nodosum Conrad. 18165. 



VIRGINIA ORISKANY AND ITS FA UNA 



In the northwestern part of Virginia, adjoining West Virginia and 

 Maryland, the Oriskany is probably not less than 300 feet thick. It is 



