348 
CEMENT MATERIALS AND INDUSTRY. 
[BULL. 243. 
The following analysis is of the natural cement made at Howes 
Cave by the Helderberg Portland Cement Company: 
Analysis of natural cement, Schoharie County, N. Y. 
Silica (Si0 2 ) 26. 54 
Alumina ( A1 2 :} ) ^ 
Iron oxide ( Fe 2 3 ) J 5 ' 89 
Lime (CaO) 1 45. 30 
Magnesia (MgO) 17. 06 
CENTRAL NEW YORK. 
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 L 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 west until it pinches out 
entirely in the Split Rock quarries, but reappearing again at Marcellus 
Kails, where it is almost 3 feet thick, and showing a thickness of 
slightly over 4 feet at Skaneateles Falls. At this 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-J feet; 
thick. The lower bed is less variable in thickness, ranging from 4 to 
a trifle over 5 feet. 
The entire cement series is overlain 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. 
Analyses of natural-cement rock, central New York. 
Silica (Si0 2 ) 
Alumina ( Al 2 ;f ) 
Iron oxide (Fe 2 3 ) . . . 
Lime (CaO) 
Magnesia (MgO) 
Carbon dioxide (C0 2 ) 
Water 
1 
10.97 
4.46 
1.54 
27.51 
16.90 
37. 94 
n. d. 
10.95 
5.32 
1.30 
30.92 
13. 64 
38.31 
n.d. 
13.50 
1.25 
25.24 
18.80 
39. 80 
1.41 
4 
5 
r 8.95 
11.76 
I 4. 90 
2.73 
1.75 
1.50 
27. 35 
25. 00 
16.70 
17.83 
38. 65 
39.33 
1.70 
1.50 
<•. 
10.66 
4. 35 
1 . 47 
27. 20 
16.77 
38. 81 
1.53 
1. Qpper cement bed, E. B. Alvord quarry, Jamesville, Onondaga Countv. Bull. 44, N. Y. State 
Mus., p. sou. 
J. Lower cement bed, E. B. Alvord quarry, Jamesville, Onondaga Countv. Bull. 44, N. Y. State 
Mus., ]>. 806. 
'■>. one and one-half miles west of Manlius, Onondaga Countv. 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. " Mini 
eralogy of New York," p. so. 
5. Cbittenango, Madison County. Seybert, analyst. Trans. Am. Philos. Soc, vol. 2, n. s., p. 229. 
6. Average of preceding live analyses. 
