IGNEOUS AND CRYSTALLINE ROCKS. 
121 
(J. Rhyolite, "Great Paint Pots." Liparose. Analysis by Gooch, 
No. 113, hitherto unpublished. 
H. Rhyolite, "Elephants Back." Porphyritic obsidian. Teham.ose. 
Analysis by Whitfield, No. 423, hitherto unpublished. Reported by 
Iddings as containing quartz, sanidine, and a little augite and mag- 
netite, in a glassy, microlitic groundmass. 
I. Rhyolite, Mount Sheridan. Tehamose. Composition reported 
by Iddings as quartz and sanidine, with a little magnetite and augite. 
Analysis by Whitfield, No. 42t>, hitherto unpublished. 
J. Rhyolite, Madison Plateau. Like I. Near diaskose. Analysis 
by Whitfield, No. 427, not yet published. 
K. Trachytic rhyolite, Elk Creek. Lassenose. Analysis by Whit- 
field, No. 428, hitherto unpublished. Reported by Iddings as con- 
taining sanidine, labradorite, and little biotite, in a groundmass of 
quartz and alkali feldspar. 
Si0 2 .. 
A1A- 
Fe 2 3 
FeO.. 
MgO . 
CaO. 
Na„0. 
H 2 0. 
Ti0 2 
PA 
MnO 
Li 2 
JS0 3 . 
75.71 
11.11 
1.56 
.37 
.08 
.88 
4.64 
4.18 
.35 
1.25 
100. 20 
75. 34 
12.51 
.42 
1.55 
.32 
1.07 
3. 31 
4.17 
.86 
none 
none 
.07 
trace 
.42 
100. 04 
75.89 
12.27 
1.12 
1.37 
.29 
.86 
3. 23 
3.42 
.82 
.50 
none 
none 
.01 
.28 
J. 
100.06 
75. 19 
13. 77 
.61 
1.37 
.09 
.68 
3. 83 
3. 33 
.65 
none 
none 
trace 
.02 
.29 
K. 
99. 83 
64. 65 
17.80 
2.33 
2.10 
.81 
1.73 
4.18 
2.83 
3. 06 
truce 
trace 
trace 
.17 
.43 
1 00. 09 
