CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
91 
L. Altered quartzite. Contains more fibrous chlorite, some sericite 
a little kaolin 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. 578. P. R. 
C. 1021. 
N. Purplish slate, containing many small crystals of red feldspar and 
scales of mica. Analyses 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. ion. 
Material for analysis dried at 104 o -105°. 
Si0 2 .. 
A1A- 
Fe 2 3 
FeO._ 
MgO. 
CaO.. 
Na 2 0. 
K 2 0.. 
H 2 0.- 
Ti0 2 .. 
PA . 
MnO. 
Li 2 . 
SO, .. 
71.00 
12.88 
6.69 
.65 
1.68 
.21 
1.43 
2.95 
2.03 
.44 
trace 
99.96 
M. 
N. 
72.25 
10.73 
8.01 
.38 
1.85 
.42 
2.03 
2.56 
2.05 
trace 
trace 
100. 28 
63. 82 
14.65 
3. 16 
5. 12 
2.08 
.70 
1.95 
2.81 
2.62 
2.66 
.19 
none 
none 
.33 
100.09 
0. 
59. 71 
18.32 
8.11 
.85 
3. 54 
1.05 
1.93 
3.43 
3.24 
trace 
100. 18 
Ba and Sr not looked for. 
