228 C. S. Grosser — Upper Hamilton and 



Of the twenty species named in the above list fourteen are 

 known to occur above the Hamilton, while five of the 

 remainder are reported from the Hamilton of eastern New 

 York, which as stated above needs revising since some of the 

 so-called Hamilton horizons are in the Portage, and only one 

 species so far as previously known occurred no higher than 

 the Hamilton stage. 



At Sidney, twenty-one miles southwest of Oneonta, the top 

 of the Oneonta sandstone is reached in the hill forming the 

 divide between the Susquehanna and Unadilla Rivers north- 

 west of the village. 



In Secor's quarry, about 140 feet above the railroad level 

 at Sidney* are grayish to olive standstones with greenish and 

 bluish argillaceous shales. Plant and crinoid stems were found 

 in the debris of the quarry, while near the top of the hill are 

 loose slabs, with no indications of having been moved any 

 considerable distance, containing poorly preserved specimens 

 of Leiorhynchus and Lamellibranchs. At New Berlin 

 Junction on the Ontario & Western R. R., two miles from 

 Sidney, or at Bainbridge five miles down the Susquehanna 

 River are numerous specimens of fossils which in both cases 

 overlay the zone of the Oneonta sandstone. 



The difficulty in correlating these deposits in which part of 

 the stratigraphic series has disappeared and paleontologically 

 many of the species common in the rocks below reappear in 

 the higher rocks, in some cases unchanged and again slightly 

 modified, may be overcome, it is believed, by carefully study- 

 ing both the fauna and the stratigraphic relations of the rocks. 

 This test has been made by the writer in southeastern New 

 York and eastern Pennsylvania, where in the absence of 

 the Tully limestone and Genesee shale, the problem is about 

 the same as that presented along the Susquehanna River 

 valley, and he believes it possible to separate the Hamilton 

 from the overlying rocks of Portage age by the faunas con- 

 tained in the respective stages. 



belongs stratigraphically above the horizon of the Tully limestone and Genesee 

 shale. Consequently it was considered best to give a separate column to those 

 species separated from the Hamilton of eastern New York, some of which should 

 probably be credited to the Portage. 



§ Most of the species given in this column are from central and western New 

 York. 



I Mainly from Ithaca and vicinity, forming the middle Portage of that region. 



•j[ This is the Oneonta zone of Conrad and the occurrence of the species at 

 other localities than Oneonta, mainly from Norwich and Mt. Upton, Chenango 

 County, is given. 



** The species reported from the Portage of eastern New York and Pennsyl- 

 vania are mainly from my own lists. 



* Elevation of station at Sidney 992' A. T. 



