44 W. A. Yertviebe — Correlation of the 



Catskill sediments are clearly recognizable as far west as 

 McKean and eastern Warren county in Pennsylvania. It is 

 this time unit which witnessed the deposition of the Bradford- 

 ian rocks in western Pennsylvania and southwestern Xew 

 York. 



It is also quite probable that this time interval is not entirely 

 included in the ordinarily accepted meaning or range of the 

 terra Chemung in New York state. At least present evidence 

 indicates that it is missing except in a few outliers, as the Olean 

 region of New York. 



The question of the age of the Bradfordian rocks is admit- 

 tedly a difficult one. Mr. Butts thinks the evidence favors 

 considering them as Carboniferous in age; however, he does not 

 wish to take a definite stand and therefore treats them under 

 the term Devono-Carbonif erons. It may be of value to bring for- 

 ward some additional evidence on this point. In a paper on 

 the "Geologic Age of the Bedford Shale of Ohio," Mr. Girty^ 

 states in reference to the fauna described from the Bradfordian 

 of New York: "The Carboniferous types cited by Mr. Butts 

 make up a total of but seven out of a list of fifty-nine species. 

 All the rest are Devonian forms most of which and possibly 

 all have never been found in rocks of Carboniferous age, so 

 that were we to consider the question whether the faunas show 

 a predominating Devonian or Carboniferous facies, there could 

 be but one answer." In the same article he also states that the 

 Bedford fauna, though peculiar, should be considered Devonian. 

 And, since the Bedford has been shown to be the time equiva- 

 lent of the Bradfordian it implies Devonian age for this series 

 as well. 



J. M. Clarke in an article on the "Construction of the Olean 

 Pock Section" states : "With proper regard for such modifi- 

 cations as additional evidence may require I am disposed to the 

 conviction tliat in placing the dividing line between Devonic 

 and Carbonic at the base of the Cattaraugus beds, as is done 

 on the geologic map, we have the support of the most direct 

 evidence. t 



Mr. Glenn, who first carefully described the Bradfordian 

 rocks in New York, concludes : "Because of the thickness of 

 these red beds (in the Cattaraugus) and their reasonably certain 

 stratigraphic equivalence with the red beds of the Catskill to 

 the east, and because of the unconformity believed to exist 

 between the Cattaraugus and Oswayo, the writer prefers to 

 draw a provisional boundary between the Devonic and Car- 

 bonic at this point.":}: 



* Ann. N. Y. Acad. Sci., vol. xxii, p. 307, 

 t Rept. N. Y. State Pal. for 1902, p. 999. 

 X Op. cit. p. 985. 



