142 PALEONTOLOGY OF NEW YORK. 



granular limestone which contains numerous species of Encrinites and a 

 l.w corals and shells. [From these, and from other observations of earlier 

 and later date, the limestones of the Falls of the Ohio have been considered 

 the i'<mivalent of the Corniferous limestone (= Onondaga and Corniferous 

 limestones), and generally of the limestones of the Upper Helderberg group 

 of New York.] 



These authors recognize the black slate, above the limestone of the Falls, as 

 having a thickness of 104 feet. 



■- 



At a later period Major Sidney S. Lyon published a table of the " Strati- 

 graphical Arrangement of the Rocks of Kentucky," in which he gives the following 

 table of the beds at the Falls of the Ohio and vicinity : 



q Black slate [= Genesee slate], u Nucleocrinus bed. 



r Encrinital limestone* v Turbo bed. 



s Hydraulic limestone. w Coral beds. 



t Spirifer bed. x Catenipora beds [ = Niagara formation]. 



The beds from rto » inclusive have been regarded, I believe, by all 

 geologists as the equivalent of the Upper Helderberg limestones of New York ; 

 and without critical examination of rocks in place, or a careful comparison of 

 the fossils contained in the several beds, I have heretofore accepted this 

 determination, and aided in the dissemination of this opinion. 



This view seems in fact to have been unavoidable, since the fossils from the 

 limestones at the Falls of the Ohio have been collected and widely distributed 

 throughout the country without reference to the successive beds of the forma- 

 tion from which they had been obtained. More recently my attention has 

 been called to the vertical distribution of the species in these rocks, and 

 during the printing of the earlier pages of this volume, I became doubtful 

 of the real identity of the higher beds with the New York limestones ; and 

 in considering the numerous species of characteristic' Hamilton fossils which 



* In thin table, the tfain-beddw] or slaty siliceous Hmentooa, with Chonktks and many Other fossils, is not 

 (lixtiiM-tly recognized, although it is really au important member. 



