2G4 ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [bull. 168. 
MICHIGAN, WISCONSIN, MINNESOTA, CANADA. 
Most of the rocks considered under this heading were described by 
Irving and Van Hise in Mon. XIX, pages 131 and 191. A few other 
analyses, also representing Van Hise's collections, are taken from the 
laboratory records. The Canadian rocks are from near the boundary 
line, and relate directly to others gathered upon the Minnesota side. 
A. Dolomite, near Sunday Lake, Gogebic district, Michigan. Anal- 
ysis by W. F. Hillebrand, record No. 767. 
B. Dolomite, Penokee region, Wisconsin, NW. I sec. 22, T. 4A N., 
R. 5 W. Analysis by Hillebrand, record No. 768. 
C. Limestone, bed of Slate Creek, Huron Bay slate quarries, Michi- 
gan. Analysis by T. M. Chatard, record No. 894. From laboratory 
records; not in the monograph cited. 
D. Limestone, east end of Ogiskemannissi Lake, Minnesota. Anal- 
ysis by Chatard, record No. 899. Not in monograph. 
A. 
B. 
C 
D. 
Si0 2 
3.07 
.63 
7.05 
41.99 
A1,0, 
. 48 1. 24 
1. 33 - 42 
Fe 2 3 
.09 
.86 
.15 
29.72 
19.95 
| .30 
.03 
.75 
.08 
30.94 
20.68 
.27 
FeO 
undet. 
.19 
50.08 
.57 
4.77 
.26 
16.85 
8.41 
.05 
1.02 
.05 
24.70 
.32 
MnO 
CaO 
MgO 
H 2 at 105° 
H 2 ign 
.25 
.27 
39.68 
.21 
p,0, 
C0 2 
45.31 
46.27 
SOo 
CI 
trace 
trace 
99.45 
99. 65 
100. 11 
100. 08 
