217 Devonian of Southern Indiana 89 



led him to modify this statement by saying: "I was led to 

 question the inference as to absolute identity. "-^^ The beds were 

 classed by Hall as Carboniferous. Prof. Hall explained his ap- 

 plication of the term "sub-carboniferous" to the upper sandstone 

 and shales of the Knobs in the following words: "The more 

 friable and micaceous sandstones above containing fossils of true 

 Carboniferous types, I called sub-carboniferous from the facfl that 

 up to that time I was not aware that anything below the base of 

 the great Carboniferous limestone had been recognized as belong- 

 ing to the Carboniferous period."! 



The correlation of the shal}^ beds below the sandstone with the 

 Portage and Chemung groups was based solely upon their litho- 

 logical resemblance to the New York formations. Hall states 

 that he was unable to find fossils within two hundred feet above 

 the Black shales. Fossils have been found in abundance in these 

 beds since Hall's examination of them, and their fauna is now 

 known to present almost as strongly marked Carboniferous af- 

 finities as that of the sandstones above. 



In an elaborate paper on the parallelism of American and Euro- 

 pean palaeozaic formations, the distinguished geologist de Verneuil 

 expressed the opinion that "in the states of Indiana, Kentucky, 

 and Tennessee the Carboniferous system comprises all of the 

 micaceous sandstone as far as the Black shales, their lower beds 

 including true Carboniferous species such as the Spirifer striahis, 

 ProduHiis pun flatus, etc."| 



The beds above the Black shale were divided into three groups 

 by de Verneuil, as follows: || 



f Sandstones, shales, and limestones 

 I of the coals. 

 Carboniferous System. \ Carboniferous limestone. 



I Fine grained micaceous sand- 

 L stone. 



The discussion of the parallelism of eastern and western form- 

 ations was resumed b}' Prof. Hall again in 1850.^5 He seemed 



*Trans. Am. Assoc. Geol, and Nat., vol. i, p. 28. 



JAm. Jour. Sci., ad. ser., vol. 7, p. 46, 1849. 



||Ib. 



^Foster and Whitney's Rept. on Geol. L. Sup. Land. Dist., pt. 2, p. 307- 



