90 



Report of the State Gteologist. 



Cazenovia group, which is a part of the Hamilton formation of the final 

 classification, and is below the Tully limestone. 1 No. 21, the "Black slate" of 

 Conrad, is the Marcellus shale ; the " shales near Apulia," " Sherburne group " 

 and " Cazenovia group " belong to the Hamilton formation, while the "Oneonta 

 group " belongs to the Ithaca group. The names Sherburne, Cazenovia and 

 Oneonta groups were apparently proposed by Conrad, and it is important to 

 observe that Vanuxem, in 1840, used two of these names for formations in a 

 different sense from that in which Conrad applied them. The "Sherburne 

 flagstones," of Vanuxem, being above the Tully limestone, and in the Portage 

 group of the final reports; the "Sherburne group" of Conrad, below the Tully 

 limestone and in the Hamilton group. The " Oneonta sandstone 11 of Vanuxem 

 referred to the heavy greenish-grey and red sandstones in the wpper part of 

 the hills, near Oneonta, while the "Oneonta group" of Conrad, as shown by 

 the fossils which he described therefrom, was composed of the bluish shales 

 and sandstones in the lower part of the hills and along the Susquehanna river 

 valley, in the vicinity of Oneonta. 2 The Chemung and Catskill groups, Conrad 

 regarded as belonging to the "Old Red Sandstone" or the Devonian system. 3 



In 1842, Conrad published a paper entitled "Observations on the Silurian 

 and Devonian Systems of the United States, with Descriptions of New 

 Organic Remains," in which he drew the dividing line between the Devonian 

 and Silurian at the base of the Ithaca group. Conrad stated that "the rocks 

 of the Ithaca group, Chemung group and the Old Red Sandstone, near Bloss- 

 burg, in Pennsylvania, constitute the Devonian system as developed in 

 Europe, and contain a number of the organic remains which characterize the 

 Devonian. * * * The lower or Ithaca rocks, many hundred feet thick, 

 contain quite a distinct class of fossils, either from the Silurian below or from 

 the Chemung strata above. The Chemung rocks, 1 have ascertained, hold 

 many forms analogous to the rocks of Devon, which constitute the Devonian 

 system, and some identical species." 4 



Final New York Reports. — The reports of 1841 closed the series of the 

 annual reports of the New York geologists. Their final reports were the next 

 publications, those of Emmons and Vanuxem appearing in 1S42, and, in the 

 following year, those of Mather and Hall. The Ithaca group, together with 

 the formations immediately underlying and overlying it, does not occur in the 



1 In reference to the stratigraphic position of the Cazenovia group, see Prosser in American Journal of Science, third series, 

 Vol XLVI, 1893, p. 214. 



2 Sec Prosser in Proceedings American Association Advancement of Science, Vol. XXXVI, 1887, p. 210; and American 

 Journal of Science, third series, Vol. XLVI, 189), pp. 214, 215. 



3 Fifth Annual Report, Palaeontology New York (Assembly Doc. No. 160, 1841 1, p 41 



4 Journal Academy Natural Sciences, Philadelphia. Vol VIII, p. 232. 



