94 



Report of the State Geologist. 



wanting in the more characteristic of the Chemung species, and its whole 

 facies links it as intimately with the Hamilton as with the typical Chemung 

 fauna." 1 



Finally, Williams, in describing the Genesee section of w estern New York, 

 says that not a trace of the Ithaca fauna is seen in Wyoming and Allegany 

 counties. The Cayuga lake section was briefly described in this bulletin, the 

 author characterizing the Ithaca group as follows: "A rich fauna, the Ithaca 

 fauna, is found in that section [Cayuga lake] before the termination of the 

 Portage fauna, but in its species it resembles both the eastern Hamilton fauna 

 and the true Chemung fauna. The studies of its species, and of those occur- 

 ring above, proves that it represents an earlier stage than that of the Chemung 

 fauna, and that it lies below as well as above deposits containing the genuine 

 Portage fauna." a 



In IS 93, Prosser reviewed the section of the Ithaca group and limiting 

 formations as exposed near Ithaca, and discussed the correlation of beds of 

 similar age farther east. 3 Professor J. M. Clarke, in 1895, reporting on held 

 work in Chenango county, discussed in a philosophical way the relation of the 

 Ithaca and Portage groups. The presence of a slightly modified Hamilton 

 fauna above the horizon of the Tully limestone and Genesee shales in the 

 Chenango valley region, as noted by Clarke, makes this paper, which later 

 we will consider more carefully when describing the geology of that valley, 

 especially important. 4 



The Chenango Valley Section". 



For several reasons it is thought best to first describe the Chenango 

 valley region before attempting to trace a dividing line between the Middle 

 and Upper Devonian of central and eastern New York. 



Tht Formations of Central New York. — In central New York, in recent 

 years, the geologic formations and series composing the Middle and Upper 

 Devonian have generally been given as follows, the base of the list being the 

 oldest : 



j— 



i American Journal of Science, third series. Vol. XXXII., p. 198. 



• Bulletin United States Geological Survey, No. 41, on the " Fossil Faunas of the Upper Devonian, the Genesee Section, New 

 York," p. 23. The date of the publication of this bulletin is given as 1887, but owing to the delay in the Government Printing 

 Office it was not published until near the close of 1888. 



• American Journal Science, third series, Vol. XL VI., p. 217. 



• Thirteenth Annual Report State Geologist [New York] for the year 1893 (1895i, pp. 552-557. 



Note — Since this paper was written Mr. Edward M. Kindle has published a bulletin on "The relation of the fauna of the 

 Ithaca group to the faunas of the Portage and Chemung'' (Bulletins American Palaeontology, Vol. II., December 25, 189t>, 06 pp , 

 3 pis.) In this bulletin Mr. Kindle <;ivesa review of the Upper Devonian in New York, which is followed by a description of 

 ten -rctinns in the virinity ol Ithaca, logethei witn lieu of species occurring in the Portage and Ithaca group- He concludes 

 that the fauna of the Ithaca group shows " a closer relationship to the Portage [than to the Chemung), and should be classed in 

 the Portage epoch." ip. 49) 



