CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
79 
L. Altered quartzite. Contains more fibrous chlorite, some sericite, 
a little kalin and biotite, grains of magnetite, earthy matter, and some- 
times a little calcite. Analysis by R. B. Riggs, record No. 570. P. R. 
C. 1009. 
M. Mottled quartzite. Analysis by Riggs, record No. 573. P. R. 
C. 1021. 
N. Purplish slate, containing many small crystals of red feldspar and 
scales of mica. Analysis by J. E. Whitfield, record No. 520. P. R. 
C. 1024. 
O. Very slightly altered slate. Analysis by Riggs, record No. 576. 
P. R. C. 1011. 
Material for analysis dried at 104°-105°. 
L. 
M. 
N. 
0. 
Si0 2 
71.00 
12.88 
6.69 
.65 
1.68 
.21 
1.43 
2.95 
2.03 
.44 
72. 25 
10.73 
8.01 
.38 
1.85 
.42 
2.03 
2.56 
2.05 
trace 
63. 82 
14.65 
3.16 
5.12 
2.08 
.70 
1. 95 
2.81 
2.62 
2.66 
.19 
none 
none 
.33 
59.71 
18.32 
8.11 
.85 
3.54 
1.05 
1.93 
3.43 
3.24 
trace 
A1 2 3 
Fe,0, 
FeO 
MgO 
CaO 
Na 2 
K 2 0. 
H 2 
Ti0 2 
P„0, 
MnO 
trace 
trace 
none 
Li 2 
so 3 
99.96 
100. 28 
100. 09 
100. 18 
Ba and Sr not looked for. 
