334 J. J. Stevenson — Use of the Name " Catskill." 



local. In southern Pennsylvania near the Maryland line its 

 whole thickness of 3700 feet disappears within less than 60 

 miles westward from the eastern outcrop ; in northern Penn- 

 sylvania it has practically disappeared before Blossburg in 

 Tioga County has been reached ; in southern New York, it 

 should not reach beyond Chemung County. It must not be 

 understood that this means that red rocks disappear ; red rocks 

 occur far below the Montrose at many places, so that rocks of 

 " the Catskill type," as Ashburner termed them, appear at 

 many localities west from the line of Catskill disappearance. 

 The Chemung extends far to the west beyond the last traces 

 of the Catskill and is easily recognized in western Pennsyl- 

 vania and in Ohio. 



The Catskill is as well defined as any group in the Devonian 

 column ; it is impossible, therefore, to discard the name as one 

 designating a subordinate division of a series, the essential 

 unity of which appears now to be conceded as fully as is the 

 unity of the Hamilton or Niagara. The question still remains, 

 however, does this Catskill portion so present the characters of 

 the whole series as to justify the application of its name to the 

 whole Upper Devonian period ? 



It is impossible to answer this question in the affirmative, 

 for were the name so employed, it would give an erroneous 

 impression respecting the conditions prevailing in by far the 

 greater part of the Appalachian basin during most of the 

 immense period represented by the Portage, Chemung and 

 Catskill. It must be remembered that the Cats-kill Mountain 

 region is not the typical area of the group which Yanuxem 

 named "Catskill." The Catskill Mountain region, far from 

 being the typical area of anything, has always been the area of 

 doubt and dispute. Mather's too hasty gathering in of the 

 red beds and Vanuxem's error respecting the relation of the 

 Oneonta to his Montrose sandstone produced uncertainty for 

 more than a third of a century and led to error in adjacent 

 regions. The work in Pennsylvania did much to prepare the 

 way for reconciliation of the facts which seemed to be at vari- 

 ance ; but Prof. Hall's recognition of the relations of the 

 Oneonta* sandstone removed the mystery and made every- 

 thing distinct. 



He has shown that the Oneonta sandstone, instead of rest- 

 ing on the Chemung, is the base on which it rests, is, in fact 

 practically, the eastward prolongation of the Portage. Mr. 

 Darton's section from Broome County of New York eastward 

 shows the same thing. 



* Hall, Fifth Ann. Report of State Geologist, Assembly Doc., No. 105, 1886, 

 p. 11. 



