104 Geological Survey of the State of New York. 



a small triangle in the north part of Stirling, Cayuga County, fif- 

 teen feet above Lake Ontario, and rising with the other rocks 

 going west, forms the lower falls of Rochester, nearly one hun- 

 dred feet above that level. 



This is followed by the gray sandstone, the same, in position 

 at least, as " the millstone grit" of Oneida, and " the gray band" 

 of Rochester. Then succeed the green shales, the iron ore beds, 

 the calcareous " firestones," &c. &c., and lastly, the concretiona- 

 ry rock of Oneida, with shales and sandstone, the upper member 

 of the " Protean group," passing from the low level near Oneida 

 Lake west, forms " the upper falls of Rochester, the rock of the 

 great excavation of Lockport, and the falls of Niagara." 



The " red sandstone" of Oswego, is the lowest rock of Madi- 

 son, Onondaga, and Cayuga, and " is the lowest rock, geologically, 

 of New York, which contains brine springs of sufficient purity to 

 be manufactured into salt." "From the east part of Oswego to 

 Niagara River, numerous brine springs are found in this red sand- 

 stone, and all which occur in this rock in the third district, (and 

 there are several in Oswego,) yield the same kind of sharp tasted 

 salt, described as the saltpetre taste, and all highly colored with 

 iron, characters different from the salt of the brine springs which 

 belong to a subsequent deposit, and show a difference of source 

 or contamination from being deposited with a different rock."^ 

 The "reof oxide of iron,''^ the "lenticular clay iron ore/' occurs in 

 " two distinct beds in the Protean group, arranged in lines, paral- 

 lel to each other, extending from Herkimer to the Genesee River, 

 about twenty-five feet from each other, and from one to two and 

 a half feet in thickness, not always present in every locality, one 

 or the other, and even both being sometimes wanting. 



The "red shale and the water limes of Herkimer and Oner- 

 da," or the " saliferous group of Onondaga" succeed, and con- 

 sist of four deposits. First, or lowest, is the red shale; second, 

 the lower gypseous shales, the lower part intermixed with red 

 shale, which ceases with this mass ; thirdly, the gypseous de- 

 posit, which embraces the great masses quarried for plaster, the 

 hopper-shaped cavities, the "vermicular lime-rock" of Eaton, and 

 other porous rocks ; and fourthly, rocks abounding in groups of 

 needleform cavities, placed side by side, caused by the crystalliza- 

 tion of sulphate of magnesia, and which may be called the mag- 

 nesian deposit. The gypseous and magnesian constituents ex- 



