142 S. G. Williams — Westward extension of Rocks 



ceeded regularly by the Oriskany sandstone without any visible 

 indications of an intervening land condition ; or whether it 

 may be interpreted as due to the persistence of species which 

 alone were adapted to the conditions of existence here pre- 

 sented, is a question to which it is not easy to give a definite 

 answer. The fact that several species indicating higher hori- 

 zons are intermingled with some of these on Cayuga Lake, and 

 that two of the Skaneateles species occur with a few others in 

 apparently correspondent strata still farther westward in On- 

 tario County (Report on 4th District, p. 141) may possibly give 

 some support to the latter hypothesis ; as may also the occur- 

 rence of S. Vanuxemi and Tentaculites gyr acanthus high up in 

 the thick Lower Helderberg series of Pennsylvania. (Report, 

 F 2 , pp. 61 and 182.) 



The exposure of Lower Helderberg rocks at Oriskany Falls, 

 eighteen miles south of Utica, is interesting, partly because it 

 is so laid open by deep and extensive quarries as to give nearly 

 a complete section of about 120 feet of rocks, 115 feet of which 

 can be definitely measured from the Oriskany sandstone, here 

 ten feet thick, down to the bank of the abandoned Chenango 

 canal ; and partly because, while highly fossiliferous at several 

 levels, it shows the condition and tendencies of the Lower 

 Helderberg limestones at a point nearly midway between Scho- 

 harie County and Cayuga Lake. The uppermost twenty-five 

 feet of limestones at this locality which are largely covered by 

 soil, where they are revealed at top and bottom, are shown to 

 be a gray, sub-crystalline rock which, where it can be reached 

 immediately beneath the Oriskany, is replete with Merista 

 arcuata and an occasional Strophodonla radiata. At the base of 

 this series of gray beds is a remarkable seam, about a foot thick, 

 filled with Peniamerus galeatus and P. Verneuilli, Rhynchonella 

 muhtbilis and R. altiplicata, Alrypa reticularis, Orthis concinna, 

 Strophodonla varistriata, S. punctulifera and *S'. planulata, and 

 occasionally Spirifera Saffordi and several other species, the 

 same fossils being also somewhat abundant in the three to four 

 feet above this seam which are opened by the quarries. In- 

 deed the difficulty in establishing any divisions like those 

 farther eastward, is not, as Professor Vanuxem found it here 

 forty-five years ago, from a scarcity of fossils, but from the 

 complete intermingling of Lower Pentamerus and Shaly Lime 

 species, both in these beds and in the limestones for fully forty 

 feet below them. Just beneath the Oriskany indeed, at the 

 single point where it could be conveniently reached, I found 

 only the two Shaly Lime species that have been named ; but it 

 is quite possible that this is merely a casual occurrence, and 

 that were these beds as thoroughly opened as those below, the 

 same intermingling of species would be found to hold good. 



