20S J\ r . II Darton — Oneonta and Chemung Formations, etc. 



but now known to be Hamilton. Mr. C. S. Prosser* in a recent 

 paper on the Devonian system of eastern Pennsylvania, de- 

 scribes the relations along the Delaware, Lackawanna and 

 Western Railroad in Monroe County west of Stroudsburg and 

 shows that Hamilton fossils occur up to the base of the red 

 beds which have heretofore been considered " Catskill " in 

 age. It is probable that these basal red beds to which he 

 refers will be found to be Oneonta for the first 1,000 feet or 

 more, with the overlying Chemung indistinguishable, as in the 

 Catskill Mountain region. 



The status of the name " Catskill? — Catskill has been used 

 as a geologic designation with such variable stratigraphic sig- 

 nificance that its status as a formation name is worthy of 

 serious reconsideration. No one can fail to be impressed with 

 this who reads Prof. Stevenson'sf admirably clear and exhaus- 

 tive review of upper Devonian stratigraphy, or has followed the 

 various controversies on the geology of southern New York and 

 northern Pennsylvania. The typical "Catskill" region is of 

 course the Catskill Mountains and in this region the name was 

 intended to comprise all of the great mass of gray sandstones 

 and red shales up to the base of the doubtful conglomerate 

 capping the higher summits. Rocks of this character overlie 

 the fossiliferons Chemung shales westward, and it has hereto- 

 fore been supposed in the Catskill Mountains that the} 7 were 

 similarly underlain by representatives of the Chemung. This 

 as I have found proves to have been a mistake and the red 

 and gray rocks of the Catskill Mountains — the type locality — 

 comprise not only the Chemung but also the Portage horizons. 

 The term Catskill has been applied in the past to beds of a 

 certain lithologic character — the hard sandstones and red 

 shales — and it has had no definite stratigraphic significance. 

 This fact has been realized in the case of the upper members 

 westward, but the determination of the true stratigraphic range 

 in the Catskill Mountains throws additional light on the matter. 



The rocks of the Catskill Mountains, and beds of similar 

 character westward, have no distinctive fauna of stratigraphic 

 significance and they cannot be correlated on paleontologic 

 grounds. The lowest red beds have often been used as a cri- 

 terion of discrimination between Chemung and Catskill, but 

 they vary in stratigraphic position from the upper beds of 

 the Hamilton in eastern New York to near the base of the 

 Lower Carboniferous in northwestern Pennsylvania, a differ- 

 ence in horizon of several thousand feet. The Chemung 



*This Journ., Ill, vol. xliv, pp. 210-221. 



f Address of Vice- President, "The Chemung and Catskill (Upper Devonian) on 

 the eastern side of the Appalachian Basin, Am. Assoc. Adv. Science, Proc, vol. 

 xl, pp. 219-247. 



