RAW MATERIAL: NATURAL-CEMENT ROCK. 



209 



The cement industry in central New York is at present practically 

 confined to Onondaga County, though as a matter of historical interest 

 it may be noted that the first natural cement made in the United States 

 was manufactured in 1818 in Madison County. 



The natural-cement rock of this central district occurs in two beds 

 which are usually separated by 1 to 4 feet of blue limestone. The 

 upper cement-bed is a little over 4 feet thick at the eastern border of 

 Onondaga County, becoming thinner to the westward until it pinches 

 out entirely in the the Split Rock quarries, but reappearing again at 

 Marcellus Falls, where it is almost 3 feet thick and showing a thick- 

 ness of slightly over 4 feet at Skaneateles Falls. At this last point 

 it is separated from the lower cement-bed only by a shaly parting a 

 few inches thick, so that the two are worked together as practically 

 one bed 9^ feet thick. The lower bed is less variable in thickness, 

 ranging from 4 to a trifle over 5 feet. 



The entire cement series is overlaid by purer limestones, but the 

 cement-rock quarries are usually located at points where these over- 

 lying limestones are thin and can be readily stripped. 



TABLE 95. 



ANALYSES OF NATURAL-CEMENT ROCK, CENTRAL NEW YORK. 



1. Upper cement-bed, E. B. Alvord quarry, Jamesville, Onondaga County. Bull. 44 N. Y. State 



Mus., p. 806. 



2. Lower cement-bed, E. B. Alvord quarry, Jamesville, Onondaga County. Bull. 44 N. Y. State 



Mus., p. 806. 



3. One and one half miles west of Manlius, Onondaga County. L. C. Beck, analyst. "Mineralogy 



of New York", p. 81. 



4. One and one half miles southwest of Chittenango, Madison County. L. C. Beck, analyst. 



"Mineralogy of New York", p. 80. 



5. Chittenango, Madison County. Seybert, analyst. Trans. Am. Philos. Soc., vol. 2, n. s., p. 229. 



6. Average of preceding five analyses. 



In Erie County natural-cement plants have long been established 

 at Akron and Buffalo. The bed of cement rock used varies in thick- 

 ness from 5 to 8 feet. " It is a firm, fine-grained compact rock of a 

 blue-gray color, weathering to a yellowish white. The Buffalo plant 



