UPPER ORISKANY OF NEW YORK 303 



It was not until 1859 that the Oriskany fauna became well known. 

 In that year Hall, the state geologist of New York, published his epoch- 

 making volume, " Palseontology in of the Natural History of New York, 

 Part vi." Below is given a complete list of the known, typical, New 

 York Oriskany fauna, the Upper Oriskany, or, as Clarke* lias named it, 

 the " Hipparionyx fauna." Regarding this fauna Hall f wrote : 



" The great changes in the physical conditions supervening at the close of the 

 preceding group [Helderbergian] indicate an influence which would affect in an 

 equal manner the fauna of the succeeding one, and we find accordingly few species 

 passing from the Lower Helderberg group to the Oriskany sandstone. The changes, 

 however, are mainly of a specific character; no new genera being introduced, so 

 far as t- nown, though some of them appear under modified forms." 



After pointing out the characteristics of the Oriskany fauna, he con- 

 cludes as follows : 



" It is not possible, therefore, to point out any changes in the fauna of i his period 

 sufficient to indicate the commencement of a new system, and its relations with 

 the formations below are as intimate as with those above, while in the northern 

 and middle states, the Oriskany sandstone bears in its fauna a closer relation to the 

 lower than to the overlying formations." 



In the Lower Oriskany fauna discovered by Beecher and worked out 

 by Clarke, as described beyond, there is no appreciable break between 

 the Becraft and the Oriskany, either in deposition or in the successive 

 faunal links. Until very recently, but 14 forms were known to be com- 

 mon to the Helderbergian and Oriskanian, but there are now 31 (24 in 

 New York) species. 



FAUNA OF THE UPPER ORISKANY, OR HIPPARIONYX ZONE 



Favosiles hemisphericus Troost. Hall collection, Albany. 



Pholidops armaria Hall. 



Orbiculoidea ampla Hall. 26054. 



Chonostrophia complanata Hall. 281 OS, 10643. 



Ortkis ( Rhipidomella) muscidosa Hall. 4882. 



Anoplia nucleata Hall. 10644. 



Leptxna rhomboidalis ventricosa Hall. Hall collection, Albany. 



Stropheodonta linchlstmi Hall. 10640, 10641, 26056. 



Stropheodonta (Leptostrophia) magnifica Hall. 4885, 5082. 



Stropheodonta (LeptostropJua) magniventer Hall. 4805. 



Stroplieodonta vascularia Hall. 



Hipparionyx proximus Vanuxem. 4217, 4227, 4809, 10638, 26060, 28107. 



CamarotcecJtia barrandei Hall. 4816. 



* Amer. Jour. Sci., November, 1892, p. 411. 

 fPal. N. Y., vol. iii, 1859, pp. 401- . 



