No. 136.] 



51 



ONEIDA CONGLOMERATE. 



In Central New York it is but a few feet in thickness, and indeed 

 seems to be entirely wanting in many places ; but on the Hudson 

 it swells to a thickness of several hundred feet, and forms the 

 Shawangunk mountain near Rondout. From this place its up- 

 heaved edges may be traced in the range of hills southeast of 

 the Delaware and Hudson Canal, and the same rock forms most 

 of the mountain range of the Kittatinny or Blue Ridge, along 

 which the Delaware flows from where it leaves New- York to 

 where it breaks through the barrier at the famous Water Gap. 

 From this point, its edge ranges southward to Virginia. No fossils 

 have yet been discovered in it : indeed the rolled and worn con- 

 dition of its materials would indicate that it was formed under 

 agitated waters, which would not allow the growth or preserva- 

 tion of organic forms. 



The source from which such enormous quantities of rolled 

 pebbles of quartz could have been derived, and the mode by 

 which they could have been spread so widely on the ocean bed, 

 is a very obscure question in geolog}^ (Several other, such for- 

 mations of conglomerate are known, two of which occur at the 

 lower and middle parts of the great Carboniferous System, of 

 which we shall speak hereafter.) 



The next succeeding series of strata are those known, from a 

 locality in Orleans county where they are well seen, as the 



MEDINA SANDSTONES. 



They are a huge mass of sandy and shaly rock, of very variable 

 hardness from soft marl to hard sandstone, and varying in color 

 from deep red to olive and light gray. They are not known in 

 the far West, seeming to thin out and disappear before reaching 

 Wisconsin, but are well seen on the Niagara river, where they 

 form most of the precipice near Lewiston. At this point the 

 lower part is a soft red shale, with harder and lighter-colored 

 layers above, to one heavy bed of which the cables of the Lewis- 

 ton suspension bridge are fastened. These sandstones may also 

 be seen in the lower part of the river cliiFs, extending as far up 

 as the upper Suspension Bridge, The same rocks are quarried 

 near the lower town of Lockport for building and flagging stone, 

 and they form the lower falls of the Genesee at Rochester, at the 

 top of which the uppermost hard layer, called the '* Gray band,'^ 



