prosser.] EXTENSION OF CHEMUNG FORMATION. 11 
Spirifera rnesastrialis Hall (c) 
Spirifera mesacostalis Hall (rr) 
Nucula corbuliformis Hall (rr) 
Orthouota undulata Con (rr) 
Tentaculites sp". (rr) 
Lingulasp (rr) 
Orthoceras sp * (rr) 
Pleurotomaria or Cyclonenia sp (rr) 
The rocks from which the above fauna was obtained are a typical 
exposure of those which have been called Chemung by Prof. I. 0. 
White in eastern Pennsylvania, hi describing this exposure Prof. 
White said: u Along the county road, about one-half mile below 
Spragueville, the Chemung rocks are seen in cliffs of gray line-grained 
sandstone, quite fossiliferous ; " l and in his account of the geologic 
formations he further stated that : "It was impossible to identify any 
of the beds between the base of the Catskill and the top of the Hamil- 
ton with the Portage series of other portions of Pennsylvania, either 
on lithological or palceontological grounds, and hence I have applied 
the name Chemung to the entire interval, preferring to regard the Port- 
age series as absent from this district." 2 Several reasons are given for 
this correlation, that of first importance being " the occurrence of char- 
acteristic Chemung fossils throughout the entire interval. ' J Later, in 
describing the geology of the Susquehanna River region, Prof. White 
stated that probably the beds in the lower part of the Chemung "are 
the equivalents of the Portage beds in New York;-' 4 and in a letter 
dated February 22, 1892, emphasizes the fact that he wishes the above 
statement to apply to Monroe and Pike Counties, and that the lower 
part of the terrane called Chemung in those counties corresponds to 
the Portage of New York. 
The fauna of this formation is not characteristic of the Chemung 
stage of southern, central, and western New York, or even of the 
highest fossiliferous pre-Carboniferous rocks of southern Pennsylvania 
and western Maryland. On the contrary, it is a modified Hamilton 
fauna, similar to the faunas that occur in central and eastern New 
York in the Portage, especially after the Tally limestone and .Genesee 
shale have disappeared. It hardly seems to be so late as the "Ithaca 
group," but rather approaches the earlier modified stages of the Ham 
ilton fauna, as possibly the Paracyclas lirata stage of Dr. II. S. 
Williams, which is found well developed above the horizon of the 
Genesee shale at Oneonta and Norwich in central New York. 5 
'G- 6 , p. 272. 
-Ibid., p. 104. 
■Ibid., p. 104. 
'G 7 , 1883, p. 68 ; and see pp. 70 and 228 for similar statements. 
*See Prof. H. S. Williams in Proc. Am. Assoc. Adv. Sci., Vol. XXXIV, p. 225 and chart; and 
Prosser, ibid., Vol. XXXVI, p. 210. This fauna characterized the Oneonta group of Conrad (not 
Vanuxem, who applied the same name to the overlying gray and red sandstones and shales), which 
was composed of bluish shales with some sandstones and abundantly fossiliferous. The zone is well 
exposed in the quarry at the foot of the hill west of Oneonta, at Norwich in the quarry near the 
reservoir, and in the lower part of the high hill west of the village. For Conrad's description of the 
"group" see Ann. Geol. Kept., N. Y., 1841, pp. 30, 31, 50, and 53. 
