250 ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. 
[bull. 168. 
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 ct cotton rock," same locality. 
D. From the Surprise mine, Joplin, Missouri. 
Analyses Ixy E. A. Schneider, record No. 1205. 
Si0 2 
ALA, Fe 2 3 
MgO 
CaO 
Ignition 
A. 
B. 
C. 
98.17 
98.92 
98.71 
.83 
.48 
.43 
.01 
.02 
.02 
.05 
.03 
.03 
.78 
.42 
.50 
99.84 
99.87 
99.69 
99.46 
.29 
trace 
.04 
.34 
ioo. i; 
E. Blue chert, unaltered, Bonanza shaft, Galena, Kansas. 
F. Same locality. 
G. Altered, same locality. 
PI. 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. 
F. 
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 
1.89 
.09 
.11 
. 77 
ALA, FeA 
MgO 
CaO 
Ignition . . 
99.97 
99.62 
99. 50 
99.56 
100. 19 
