40 
ANALYSES OF ROCKS, U, S. GEOLOGICAL SURVEY. [bull. 168. 
PENNSYLVANIA. 
A. Aporhyolite, Monterey, Franklin County. Described by Flor- 
ence Bascom in Bull. 150, p. 343. Contains alkali feldspars, quartz, 
sericite, epidote, titanif erous magnetite, leucoxene, and rarely sphene. 
Analysis by H. N. Stokes, record No. 1479. P. R. C. 136. 
B. Quartz-porphyry, same locality. Analyzed for G. H. Williams, 
but never described. Analysis by L. G. Eakins, record No. 1350 
A. 
B. 
Si0 2 
76.34 
11.60 
2.41 
.30 
.06 
.55 
5.50 
2.75 
.10 
.39 
.26 
trace 
trace 
.09 
trace 
73.85 
13.15 
3.27 
.36 
.32 
.82 
2.29 
5.42 
} ■« 
ALO, . • 
Fe 2 3 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 Oat 100° 
H 2 above 100° 
Ti0 2 
P„0, 
.06 
.09 
MnO.. 
BaO 
C0 2 
100. 35 
100. 34 
