JL.] 
OHIO. 
271 
CORNIFERO US LIMESTONE*. 
il The Corniferous limestones, which correspond approximately to the 
Inondaga or upper Helderberg limestones of New York, contain 
eavy beds of magnesian limestones, with a smaller amount of lime- 
lones low in magnesia. The variation in this respect that may exist 
h a single quarry is well shown by the following series of analyses 
Loted from reports of the Ohio Geological Survey: 
Variations in composition of limestone from various quarries. 
No. 
Silica (Si0 2 ) 
3.20 
4.60 
2.92 
1.35 
1.57 
1.92 
2.20 
1.65 
.85 
1.49 
1.05 
1.65 
1.00 
2.65 
1.55 
2.70 
Alumina 
(A1 2 3 ); 
iron oxide 
(Fe 2 3 ). 
4.00 
1.25 
4. 33 
6.01 
3.05 
1.85 
1.97 
2.65 
.27 
.15 
.20 
.14 
.37 
.44 
.18 
3.30 
Lime car- 
bonate 
(CaC0 3 ). 
88. 30 
80.40 
84.70 
92.00 
85.55 
74.00 
66. 15 
72.85 
97.28 
87.10 
89.16 
77.22 
89.20 
77. 23 
78.60 
65. 80 
Magnesium 
carbonate 
(MgC0 3 ). 
2.58 
13.80 
8.64 
.56 
10.39 
21.46 
27.97 
22.38 
2.00 
10.96 
9.48 
20.19 
9.64 
18. 55 
19.79 
27.95 
i Analyses 1-8 are of different beds in a quarry at Owen station, Marion County. 
Analyses 9-12 are of different beds in the Ke'lley quarries, on Kelleys Island. 
Analyses 13-16 are of beds in the Hartshorn quarries, on the Marblehead peninsula near Sandusky. 
