8 BuLJwETlN 6 8 



In his final Report* Vanuxem used the term "Catskill group" 

 for the uppermost member of the New York System which he 

 had previously called Montrose sandstone. The Catskill group 

 continued to be regarded for several years as distindl from and 

 subsequent in time of deposition to the Chemung. 



The preliminary work of the classification of the New York 

 strata according to their organic contents into the groups which 

 have since been recognized as the paleontolgic units for the 

 United States was completed with the publication of the final 

 reports of the different distridls from 1840 to 1843. 



In 1847 Edward de Verneuil visited America and correlated 

 the divisions of the New York System with the European for- 

 mations.! The divisions of the Erie and the five superior divis- 

 ions of the Helderberg he correlated with the Devonian of Eng- 

 land. He proposed to combine the Marcellus shale, Hamilton 

 group and Tully limestone into one division, and the Portage 

 and Chemung groups into a second division of the Devonian. 



The discovery in the year 1862 of fish bones of a chara(5leristic 

 Catskill species associated with Chemung fossils in the Catskill 

 rocks created doubt as to the superior position of those deposits. 

 Col. E. Jewett declared his belief that there ^ "is no Old Red 

 sandstone in the State." Prof. Hall was led by the same facft 

 to modify his views of the extent of the Catskill group. He 

 expressed the opinion that the ' 'greater part of the area colored 

 on the geological map of New York as Catskill group is in fadt 

 occupied by the Portage and Chemung. "§ 



A comparative study of the Upper Devonian faunas of New 

 York led Prof. H. S. Williams to consider the Chemung and 

 Catskill as contemporaneous formations. 1 1 



In his vice-presidential address^ in 1891 Prof. J. J. Stevenson 

 reviewed in detail the evidence bearing on the relation of the 

 Catskill to the Chemung and their extent. He considered the 

 Catskill and Chemung to have been deposited synchronously in 

 a shallow basin subsiding most rapidly to the east. 



Mr. N. H. Darton proposed** as the result of stratigraphical 

 studies in the Catskill region that ' ' Catskill ' ' be broadened 



*Geol. of N. Y., Part 3, p. 16, 1842. 



tBuU. Geol. Soc. of France, 2d ser., vol. iv. 



JAm. Jr. Sci., 2d ser., vol. xxxiv, p. 418. 



^ Can. Nat. and Jr. of Sci., new ser., vol. vii, p. 377. 



II Bull. U. S. Geol. Surv., No. 41. 



11 Proc. Am. Assoc. Adv. Sci., 1891, p. 241. 



**Am. Jr. Sci., 3d Ser., vol. xlv, pp. 203-209. 



