LIME AND CEMENT INDUSTBIES 795 



The lower member of the Niagara limestone is used only for 

 building and road material, bnt the upper member, or Guelph, 

 is extensively sought for lime-making. 



In quarrying it for this purpose the massive layers are preferred 

 to the cellular ones, as it is claimed that they yield a better grade 

 of lime. Owing to its magnesian character, the lime is not very 

 fat and consequently does not develop as much heat in slaking as 

 one made from a pure stone. 



A group of quarries is located at Snyder street and Frost ave- 

 nue, Eochester, and known as the Pike quarries (pi. 45). The 

 section exposed in the Guelph rock is about 18 feet thick, and the 

 upper 5 feet, which is free from cavities, is said to make the best 

 lime. Near the bottom is a 4 foot layer called by the quarrymen 

 the " Hogback ", which, it is claimed, does not make a good lime. 

 Some stone is being drawn from this quarry to Mrs J. Hurd's 

 limekiln at Jefferson and Seward avenues. The lime from this 

 kiln is used chiefly for mortar but is also utilized to some extent 

 by the glass works at Rochester. 



The lower member of the Magara limestone, which is not fit 

 for lime-making, is extracted on North. Goodman street near 

 Northwest avenue, in the quarries of Foery & Kastner, Whit- 

 more, Rauber & Vicinus, and Lauer & Hagaman. The stone is 

 a medium bedded, hard, fine grained, silico-magnesian limestone. 



The Guelph rock is quarried most extensively at Rochester, 

 but also at Penfield and East Penfield. Good exposures 

 occur in the quarry of Lauer and May at Brighton, 2 miles east 

 of Eochester (pi. 48). The rock is used for lime and gives a 

 lumpy product of yellowish color. The following analysis sets 

 forth well its magnesian character and its comparative freedom 

 from silica. 



Silica 1.12 



Alumina 27 



Ferric oxid 39 



Lime 29.38 



