^2 NEW YORK STATE MUSEUM 



CHAPTER 3 



NATURE AND DISTRIBUTION OF THE ORISKANY FAUNA 



IN NEW YORK 



The fauna of the calcareous Oriskany is in no sense a mixed 

 assemblage, or an intermingling of faunas of adjacent provinces. The 

 sequence of life has continued without apparent interruption from the 

 Helderbergian (Kingston beds) into the sediments of the Oriskany 

 and the Ouondaga limestone. 



It is extremely probable that important variations from the fauna 

 of the Catskill shaly (New Scotland) limestone had already made their 

 appearance in the Becraft limestone, and that we first become acquainted 

 with some of these in the study of the calcareous Oriskany. No 

 proof therefore could be adduced more emphatically confirmatory of 

 the intimate faunal relations of the Helderbergian with the Oriskany 

 fauna and its successors than the facts brought forward in this paper. 



The fauna discussed in the foregoing pages is that of the cal- 

 careous fades of the Oriskany formation. The sedimentary deposits of 

 this and neighboring sections were essentially limestones notwithstanding 

 the silicious content, whether diffused through the mass or segregated as 

 cherty secondary product. In the earlier presentation of this fauna it 

 was regarded as of lower Oriskany horizon, on account of the presence 

 of many Helderbergian species, but we believe it will be more correctly 

 construed as the representative of the proper and normal Oriskany 

 fauna, the true fauna of this time unit inclosed in the sediments of 

 its proper habitat. 



DISTRIBUTION OF THE CALCAREOUS FACIES OF THE ORISKANY IN NEW YORK 



Ulster county. A complete section of the strata from the Coeymans 

 limestone through to the summit or almost to the summit of the Oriskany 



