284 
ANALYSES OF EOCKS, U. S. GEOLOGICAL SURVEY. [bull. 168. 
OHIO. 
Three samples of Utica shale from New Vienna. Collected by 
Edward Orton. Partial analyses by F. W. Clarke and R. B. Riggs, 
record No. 731. 
A. 
B. 
c. 
Insoluble 
60.17 
17.11 
1.25 
15.24 
29.51 
33.43 
2.16 
27.16 
25.80 
35.27 
1.32 
27.40 
CaO 
MgO 
C0 2 
93.77 
92.26 
89.79 
Iron and alumina are present in the soluble portions of these shales, the solvent 
being dilute hydrochloric acid. 
MICHIGAN. 
Clay slate, sec. 17, T. 43 N., R. 31 W., near Mansfield. Contains 
principally quartz, white mica, actinolite, rutile, hematite, and car- 
bonaceous matter. Described by J. M. Clements in Mon. XXXVI, 
pp. 59, 61, 210. Analysis by George Steiger, record No. 1709. 
Si0 2 60. 28 
A1 2 3 22. 61 
Fe 2 3 2.53 
FeO 45 
MgO 1 . 35 
CaO 13 
Na 2 54 
K 2 5. 73 
H 2 at 100° 60 
H 2 above 100° 3. 62 
Ti0 2 69 
P 2 5 03 
MnO trace 
BaO 04 
C 97 
99.57 
