OEISKANY FAUNA OF BECUAFT MOUNTAIN 77 



T have not had opportunity to verify all of these identifications, biit 

 the list as it stands shows a predominance of Helderbergian species. 

 In fact, its Oriskany representation seems to me largely dependent on 

 the identity of the specimens here regarded as Spirifer a r rectus 

 (= S. murchisoni). I am satisfied that the Chonostrophia is 

 the form (C. helderbergiae) of the New Scotland beds, and at 

 all events the character of the rock shows the fossils to be an ag- 

 gloraerated mass of remains brought together by wave wash. Present 

 evidence indicates that this is not an Oriskany nor indeed a transition 

 fauna but a proper part of the Kingston limestone beds. 



Albany and Schoharie counties. To the north and west of the 

 Kingston sections, through the Helderberg mountains the Oriskany 

 f(»rmation becomes thinner and gradually loses its calcareous character. 

 On the Oniskethau creek near Clarksville it is represented by a foot 

 or tM'^o of dark compact chert. It is a gray, quartzitic sandstone 

 about two feet thick at Countryman hill, near New Salem. At the top 

 of the hill south of the Indian Ladder it has much the same character 

 and thickness and abounds in Spirifer arenosus, Sp. murchi- 

 soni, Meristella lata, etc. South of High point, near Alta- 

 mont, the rock becomes slightly calcareous. 



At Knox it is finely exposed as a compact quartz sandstone 

 though not more than 2 to 3 feet thick. 



On West mountain, Schoharie, at the house of George Acker 

 (Murphy farm), above the Becraft limestone rest about 10 feet of a 

 gray, schistose, arenaceous limestone, which terminates above in a hard 

 quartzite. The calcareous content of the rock is considerably less than 

 the silicious. Fossils are abundant : 



Rensselaeria ovoides Spirifer murchisoni 



Stroplieodonta magniventra Pholidops terminalis 



Spirifer arenosus Meristella lata, etc. 



In none of these sections can the Oriskany strata be properly 

 termed sandstone, in the sense in which that term was originally applied 

 to it in 1837. 



