Maryland Geological Survey 35 



In 1843, Prof. James Hall's final report on the Fourth District, cover- 

 ing western New York, was published, in which the classification is nearly 

 the same as that used by Vanuxem ; the only changes concerning that 

 part of the system now under consideration were the uniting of the 

 Ithaca and Chemung groups and the acceptance of Emmons' classifi- 

 cation of the Catskill division as the " Old Eed system or Old Red 

 Sandstone " ' which was a correlation with the Old Eed Sandstone of 

 England. The same year Mathers final report on the First District was 

 published in which he agreed with Vanuxem in considering the Catskill 

 as the last division of the New York System.^ He was also of the 

 opinion that the Erie division extended to the top of the Chemung, for 

 he stated that " The Erie division in the First Geological District, con- 

 sists of the following groups, viz. : 



1. Ithaca and Chemung group. 



2. Hamilton group. 



3. Marcellus shales. 



The Portage group, Genesee shales, and Tully limestone of the Erie 

 division, if they exist in the First District, have not been recognized as 

 distinct strata." * 



In 1846, Volume I of Emmons' Agriculture of New Yoik was pub- 

 lished in which he gave a lengthy account of the New York System.* 

 The classification remained aboi;t the same as in his former report; but 

 some ambiguity exists in reference to the position of the Catskill division 

 or Old Red system and the number of formations composing the Erie 

 division. It is stated tliat " The New York system admits of four 

 divisions," ° which are then listed in ascending order as 1. Champlain, 2. 

 Ontario, 3. Helderberg, and 4. Erie. These are followed by 5. Catskill.* 

 Furthermore, imder the description of the members composing these 



' Geology New York, Pt. IV, pp. 18, 19. For descriptions of tlie various 

 stages see pp. 177-284. 



= Geology New York, Pt. I, p. 299. 



^Ibid.. p. 317. 



^Chapter VI, pp. 113-200. 



^ Loc. cit., p. 114. 



'Loc. cit., pp. 115, IIG. 



