Prossee — Hamilton and Chemung Series. 



91 



Second District, consequently Emmons in his final report does not discuss 

 their relations. 



Vanuxem in his final report referred to the Portage or Nunda group, 

 the Cashaqua shale, Girardeau and Portage groups and Sherburne flagstone of 

 the annual reports. 1 



The Ithaca group remained as a distinct formation between the Portage 

 and Chemung groups. Vanuxem claimed that "the rocks at Ithaca presented 

 a different mineral appearance from those below, and from those above them ; 

 being darker colored, and the shaly part coarse, harsh, dull, and less disposed 

 to be in layers than either of them, containing numerous fossils, which were 

 wanting in the flags, etc., below; while those of the lower part of the mass at 

 Ithaca appeared to be different from those of the Chemung group." 2 And he 

 further said that it was his intention at first " to unite the Sherburne and the 

 Ithaca masses, not having discovered in the district those leading characters 

 by which they could be readily distinguished * * * but finding, on the 

 contrary, that Mr. Hall was desirous to unite the Ithaca and the Chemung 

 groups, from the little or no difference which he could perceive between them 

 in his district, and that the lower masses merited a distinct name, the original 

 arrangement was retained, and the name of Sherburne changed to Portage or 

 Nunda group." 3 



In describing the Chemung group, Vanuxem stated that " between the 

 Ithaca and Chemung group no precise line of division was observed. A high 

 ridge was seen rising above the inclined plane at Ithaca ; the rocks to the 

 south contained none of the brownish sandstone of the Ithaca, and there were 

 different fossils noticed in the two ; upon these differences the Chemung group 

 was founded." 4 



Mather's final report, describing the First Geological District or south- 

 eastern New York, appeared in 1843. Mather states that the Ithaca and 

 Chemung groups occur in the First Geological District, 5 and mentions their 

 occurrence in the southwestern townships of Albany county, 6 but does not give 

 any detailed account of the characters or distribution of these formations. 



Hall's final report was also published in 1843, in w hich the geology of 

 western New York is exhaustively described. In this report Professor Hall 

 followed the opinion announced in his annual report of 1841, and referred the 



1 Geology of New York, Part III., 1&12, p. 172. 



2 Ibid., p. 171. 



3 Ibid., p. 171. 



* Ibid., p. 179. 



* Geology of New York, Part I., p. 317. 



6 Ibid., p. 321, towns-hips of " Eensselaerville and Weeterlo, and a part of Bern." 



