Prossek — Hamilton and Chemung Series. 



1 1 3 



synchronous with those of the Portage formation in western New York, 

 differ so strikingly from the Portage in faunal and lithologic characters, 

 there would be an advantage in classifying them in such a way as to make 

 them readily recognizable in the eastern part of the State. The name Oneonta 

 formation is in general use for the upper part ; Ithaca formation to some extent 

 for the middle portion ; and if Sherburne formation be applied to the lower 

 division, there will then be a complete series of formation names for these 

 terranes, which may be readily followed and mapped half way across New- 

 York. Since the Sherburne formation may easily be followed from Sherburne 

 to Ithaca, it is proposed that these rocks at the head of Cayuga lake near 

 Ithaca be called the Sherburne formation. 



In this connection it is well to recall the fact that Conrad, in 1841, pro- 

 posed Sherburne group as the name of a formation for shales found near 

 Smyrna and other localities. 2 The fossils described by Conrad from the Sher- 

 burne group are Hamilton species, and this zone was referred correctly by 

 Vanuxem to the Hamilton formation in his final report of 1 842. 3 



As the rocks to which Conrad applied the name, " Sherburne group," 

 belong in the upper part of the Hamilton formation, there is little probability 

 that there will ever be occasion to restore the name, and, furthermore. 

 Vanuxem's name " Sherburne flagstones " antedates Conrad's by fully one 

 year, so that, according to the law of priority, Conrad's name would be lost. 



XVIII B Q . Near the top of the hill, at an approximate altitude of 

 1,620 feet A. T., is a small excavation exposing two feet of shaly sandstones. 

 The rock is bluish grey in color, and contains some fossils, especially Spiro 

 phyton, which occurs abundantly. The following species were collected at 

 this place : 



1. Oyrtma Hamiltonensis, Hall. (a) 



2. Spirifer mucronatus (Con.), Bill. (c) 



3. Spirifer mesacostalis, Hall. (rr) 



Specimens in the form of casts which show clearly the median 

 septum in the sinus of the ventral valve. 



4. Spirifer aud^yhfs (Con.), Hall and Clarke, (r) 



5. Spirifer, sp. (rr) 



Fragments of external moulds which show impressions of 

 pustules. The specimens do not have the normal form of S. granu- 

 losus; cf. S. fvmbriatms (?). 



1 Fifth Annual Report Palaeontologist, State of New York (Assembly Document No. 150, 1841. p. 31). 

 ! Ibid., see lists of fossils on pp. 50-55 for the localities. 



3 Geology of New York, Part III., p. 150. The same con elation appears in Professor Hall's Final Report of 1843 (Geology of 

 New York, Part IV., p. 184) 

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