PALEONTOLOGY OF NEW-YORK. 



ONEIDA CONGLOMERATE. 



The Oneida conglomerate marks, in a most decided and unequivocal manner, the limit between 

 the lower and middle portions of our system. Its wide extent, and, in many places, its extra- 

 ordinary development entitle it to rank as a formation of great importance. It is true that in 

 Western New-York, and in the Western States, it is comparatively unimportant ; but when we 

 pass to the southeast and to the south by the shores of the Hudson, and thence into New- Jersey, 

 Pennsylvania and Virginia, this formation becomes very powerful, forming distinct topographical 

 features. As examples of this we may instance the Shawangunk mountain in the southern part 

 of New-York, and the extension of the same range in New- Jersey in the Blue or Kittatiny 

 mountain range, which, in its southern extension, crosses the Delaware river at the Delaware 

 water-gap, and thence through Pennsylvania and the western part of Maryland into Virginia. 

 There are also numerous minor points, in Pennsylvania and Virginia, where this rock forms 

 diitinct and prominent features in the topography of the country. 



In the regular ascending order, the Oneida conglomerate succeeds the Hudson-river group. 

 It sometimes rests directly upon the shales of that group, as in Herkimer county ; or succeeds 

 a fine-grained gray sandstone, which may be regarded as terminating the Hudson-river group, 

 and forming a more natural passage into the conglomerate*. 



I have not been able to recognize any fossils in this rock : indeed its materials are of such 

 character that fossils could scarcely be preserved, and the conditions under which it was formed 

 were not favorable to the development of organic existence. 



A few fragments of what appear to be marine plants have been seen in this rock, but in all 

 too imperfect to be of any importance. 



• In Herkimer and Oneida counties, this conglomerate is closely associated with the beds of the Clinton group 

 which immediately succeed it; and being there of coarse materials, it would readily be confounded in one group with 

 the conglomerate. In the southern part of Herkimer county, the shales of the Hudson-river group are separated 

 from the sandstones and ore beds of the Clinton group only by the Oneida conglomerate, which has but a very in- 

 considerable thickness. Still farther east, along the base of the Helderberg, where the Clinton, Niagara and 

 Onondaga-salt groups are very thin, the Oneida conglomerate is absent, and the shales and sandstones of the Hudson- 

 river group rise to within a few feet of the Tentaculite limestone or Water-lime group. 

 [Paleontology — Vol. ti.] 1 



