clarke.] ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 297 
CHERT. 
From the lead-zinc region of southwestern Missouri and its exten- 
sion into Kansas. 
Collected by W. P. Jenney. 
A. Unaltered chert, East Hollow, Belleville, Jasper County, Missouri. 
B. Partly altered, same locality. 
C. Altered to "cotton rock," same locality. 
D. From the Surprise mine, Joplin, Missouri. 
Analyses by E. A. Schneider, record No. 1205. 
A. 
B. 
c. 
D. 
Si0 2 - . . 
98.17 
.83 
.01 
.05 
.78 
98.92 
.48 
.02 
.03 
.42 
98.71 
.43 
.02 
.03 
.50 
99.46 
A1 2 3 , Fe 2 3 
.29 
MgO 
trace 
CaO 
.04 
Ignition 
.34 
99.84 
99.87 
99.69 
100. 13 
E. Blue chert, unaltered, Bonanza shaft, Galena, Kansas. 
F. Same locality. 
G. Altered, same locality. 
H. Jasperite, Joplin, Missouri. 
I. Jasperite, Galena, Kansas. 
Analyses E, F, and G by E. A. Schneider, record No. 1205; H and 
I by L. G. Eakins, record No. 1208. 
E. 
E. 
G. 
H. 
I. 
Si0 2 
99.23 
.22 
trace 
.02 
.50 
98.60 
.52 
trace 
.10 
.40 
99. 13 
.16 
.01 
trace 
.20 
95. 77 
1.84 
.24 
.54 
1.17 
97.33 
ALOo, Fe 9 0, 
1.89 
MgO 
.09 
CaO 
.11 
Ignition 
.77 
99.97 
99. 62 
99.50 
99.56 
100. 19 
