194 [Assembly 



III. 



Limestones not Metamorphic, Compact or Stjbcrystalline ; theib 

 Geological and Geographical Distribution. 



The limestones used in building, or for foundations, canal locks, 

 bridge abutments and other solid masonry, are very widely distrib- 

 uted, and in great variety within the State of New York. 



In their geological order, we have the Chazy limestone^ the Tren- 

 ton limestone ^row/? (embracing the Birdseye, Black river and Tren- 

 ton limestone proper), the Niagara limestone^ the Loioer and Upper 

 Ilelderberg limestone groups, and the Tully limestone. 



These limestones vary from a dark -bluish-black or black color to 

 bluish-gray, gray, or sometimes reddish or brownish-gray. 



1. The oldest of these, the Chazy limestone, as its name indicates, 

 occurs at Chazy in New York. It forms the island known as Isle 

 la Motte, and other islands in Lake Champlain, and extends likewise 

 into Vermont and Canada. It exists in heavy beds, and is largely 

 quarried for different purposes, as will be mentioned hereafter. 



2. The Trenton limestone group, in one or more of its members, 

 occurs both on the east and west shores of Lake Champlain, and is 

 extensively quarried at Willsborough and other places. The same 

 rock occurs at Glens Falls and in the neighborhood of Saratoga 

 Springs. It likewise extends along the Mohawk valley from the 

 neighborhood of Hoffman's Ferry to Little Falls, and is quarried at 

 Amsterdam, Tribes Hill, and other places. At Little Falls the con- 

 tinuity of the limestone formation is interrupted by the southern 

 extension of the Gneiss formation, but it comes in again to the south 

 and west beyond this, and is extensively quarried at Jacksonburgh 

 on the south side of the Mohawk river. The same formation ex- 

 tends^ by the way of Trenton Falls, through Lewfs and Jefferson 

 counties, everywhere offering quarries for building-stone and for 

 lime. 



3. The Niagara limestone, though extending further to the east- 

 ward, acquires little force or thickness till we reach Monroe county, 

 where it has a considerable thickness on the Genesee river, and 

 some of the beds of the formation are valuable as quarry-stones. It 

 is only in the neighborhood of Lockport, however, that the lower 

 beds of this formation become important as a building stone. The 

 principal working beds are a light gray stone, varying in some in- 

 stances to a brownish color from the admixture of organic remains. 

 The same limestone occurs at Niagara Falls and vicinity, extending 

 thence through Canada West to Lake Huron. The upper parts of 

 the formation are of a brownish, or often of an ashen gray color, 

 with irregular bedding and of unequal texture, as well as marked by 

 cavities and crystalline masses of calc-spar, selenite or compact gyp- 

 sum, celestine, etc. The stone of this part of the formation is 

 adapted only to the heavier and coarser masonry, and care is re- 

 quired in its selection to secure a strong and durable stone. 



