Williams.] JAMES HALL ? S CORRELATIONS. 63 



or Waverly sandstone series of Ohio." ' Above this were seen " friable 

 gray sandstones with intercalated beds of oolitic limestone." 



"These rocks are marked in the section by the name k Subcarboniferous > J 

 and although the fossils and the character of the intercalated beds of 

 limestone indicate the commencement of the same era as the Carbonif- 

 erous limestone, yet it requires that a limit should be fixed between 

 what is to be strictly referred to Carboniferous and older deposits." 2 



In a foot-note the author referred to Dr. Owen's denomination of " the 

 rocks here described as well as the succeeding limestone as Subcarbon- 

 iferous,"and remarks that he had not seen the report when his section 

 was prepared. 



D. D. Owen first applied the term Subcarboniferous to the limestones 

 underlying the Coal Measures, having included with them the Silurian 

 limestones, and to the whole series be applied the designation Cliff 

 limestone. James Hall introduced the name Subcarboniferous to indi- 

 cate rocks which he regarded as lying below the " Carboniferous lime- 

 stone, " the intercalated calcareous beds of which contained fossils 

 like those of the Carboniferous era. 3 



The " Carboniferous limestone "of Hall's paper was not recognized 

 east of New Albany, Indiana, where it is reported as resting upon the 

 u Subcarboniferous rocks." From there it was traced westward, and 

 along the Mississippi Valley in Illinois, Iowa, Missouri, and Tennessee. 



The author held that upon going westward the character of the 

 deposits changes, and the nature of the species changes with indica- 

 tions of difference in depth. 



It will be seen thatllalPs interpretation was based upon tracing the 

 continuity of the strata. Though fossils were considered in a general 

 way, the differences noted were regarded as due to changed conditions 

 rather than to lapse of time. So that the more minute comparison of 

 the fossils for a long time failed to convince geologists of the errors of 

 correlation. 



The misinterpretation of the relation of the Waverly formation of 

 Ohio to the New York system was very difficult to correct, since the 

 State geologist who best knew the New York system had claimed, as 

 the result of personal examination, tracing the rocks step by step all 

 the way from New York to the Mississippi Valley, that these rocks 

 were identical. It was difficult to get people to believe in the testi- 

 mony of fossils against such assertions. 



In the year 1843 H. D. liogers 4 expressed the opinion that the black 

 bituminous shales which appear in the States west of Ohio, between 

 the Silurian and the Carboniferous, represent the Marcellus shales of 

 New York State, and in this opinion he differed with Hall, who re- 



1 Hall, James: "Nates explanatory of a section from Cleveland, Ohio, to tlie Mississippi River, in a 

 southward direction, with remarks upon 1 he identity of the western formations with those of Now 

 York. Assoc. Am. Geol., Trans. 1843, p. 280. 



2 Ibid., p. 281. 



3 See Chapter vm. 



4 Rogers, Henry I). : On Marcellus and Hamilton of the West; Am. Jour. Sci., vol. 45, 1843, pp. 161, 162. 



