CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
175 
II. Rhyolite (nevadite), from Chalk Mountain. Liparose. Mainly 
quartz and feldspar, the latter being sanidine and plagioclase. A 
little biotite, magnetite, apatite, and zircon are present. Analysis by 
Hillebrand. P. R. C. 64, 512, and 1289. 
I. Sanidine from H. Analysis by Hillebrand. P. R. C. 64. 
SiU 2 . 
A1 2 3 
Fe 2 3 
FeO . 
MgO. 
CaO . 
Na 2 
K 2 . 
H 2 0. 
PA- 
MnO 
LLO. 
100. 38 
74.45 
65.04 
14.72 
20. 40 
none 
.56 
.37 
.83 
.79 
3.97 
4.11 
4.53 
9.74 
.66 
.29 
.01 
.28 
trace 
100. 37 
