344 ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [no. '228. 
OHIO. 
Three samples of LTtica shale from New Vienna. Collected by 
Edward Orton. Partial analyses by F. W. Clarke and II. B. Riggs, 
record No. 731. 
Insoluble 
CaO 
MgO 
CO, 
60.17 
17.11 
1.25 
15.24 
93. 
B. 
29. 51 
33. 43 
2.16 
27.16 
92.26 
25. 80 
35. 27 
1.32 
27.40 
79 
Iron and alumina are present in the soluble portions of these shales, the solvent 
being dilute hydrochloric acid. 
MICHIGAN. 
A. Clay slate, sec, 17, T. 43 N., R. 31 W., near Mansfield. Con- 
tains principally quartz, white mica, actinolite, rutile, hematite, and 
carbonaceous matter. Described by J. M. Clements in Mon. XXXVI, 
pp. 59, 61, 210. Analysis by George Steiger, record No. 1709. 
B. Pink slate, from near base of Upper Huronian, Menominee dis- 
trict. Center of sec. 5, T. 39 N., R. 29 W., near Norway mine. 
Described by Bayley in Mon. XLVI, p. 298. 
C. "Briar slate," Vulcan iron formation, Menominee district, Also 
described by Bayley, loc. cit,, p. 330. 
Analyses B and C by E. T. Allen, record Nos. 1974, 1991. 
A. 
B. 
C. 
sio 2 : 
60. 28 
22. 61 
2. 53 
.45 
1. 35 
.13 
.54 
5. 73 
.60 
3.62 
.69 
.03 
67.04 
15. 01 
3. 54 
3.18 
2.11 
.19 
.29 
4.00 
.67 
3. 73 
.69 
.03 
.02 
trace 
trace 
trace 
50.15 
Al 9 0, 
6. 55 
FeA 
33. 80 
FeO 
.-94 
MgO 
. 94 
CaO 
.16 
Na 2 
.31 
K 2 
4. 38 
H 2 Oat 105° 
81 
H 2 above 105° 
1.43 
TiG 2 . 
52 
PA 
.08 
s 
CrA 
MnO .... 
trace 
.04 
.97 
BaO 
C 
99. 57 
100.50 
100. 07 
