233 Devonian of Southern Indiana 105 



Black shale and separated from it by a few feet of foetid lime- 

 stone, is correlated with the middle or upper part of the Helder- 

 berg group. 



In 1842 Prof. James Hall read a paper on the "Identity of 

 Western Formations with Those of New York" before the As- 

 sociation of Geologists and Naturalists. In this he stated:* "In 

 the Cliff limestone we have the Helderberg series of New York, 

 or at least two persistent numbers, the Onondogaand Corniferous, 

 with the Water lime and perhaps a meagre representation of the 

 Salt group, together with the Niagara limestone." 



Of the Black shale Hall says that "it seems to be the equiva- 

 lent of the Marcellus of New York and is the only representative 

 of that rock the Hamilton group and the Genesee slate, "f 



Prof. H. D. Rogers,:}: in discussing Hall's opinion of the age of 

 the Black slate, stated that he could find no trace of the Hamil- 

 ton group in. the west and regarded the Black shal^ as the equiv- 

 alent of the Marcellus shale alone. 



In a paper before the iVssociation of Geologists and Naturalists 

 in 1843 D. D. Owen expressed the opinion- that the Black shale 

 of Indiana and Kentucky was the equivalent of the Marcellus. || 



It is to Edward de Verneuil that we are indebted for a correla- 

 tion of the Paleozoic formations of Indiana and Kentucky which 

 has been very slightly modified by subsequent investigations. 

 M. de Verneuil's views on the parallelism of American and Euro- 

 pean formations were published in 1847.^ The classification of 

 the Paleozoic rocks of Ohio, Kentucky, and Indiana proposed b}^ 

 de Verneuil is as follows:^] 



(8. Sandstones, shales, and limestones of 



Carboniferous System. -{ r> u -r ' ^■ *. 



I 7. Carboniferous hmestone. 



1 6. Fine-grained micaceous sandstone. 



"■•'Trans. Am. Assoc. Geol. and Nat., p. 279. 



tibid, p. 2S0. 



JAm. Jour. Sci., vol. 45, 1843, P- 161. 



II .. .. .< .. u .< . J52_ 



?Soc. Geol. France, Bull., 2d .ser., vol. 4, if^47, pp. 646-709. 

 IjAni. Jour. Sci., vol. 5, 2d ser. 1848, p. 183. 



