236 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [no. 228. 
10. CALAVERAS COUNTY. 
Rocks collected by H. W. Turner, and described in 14th Ann., p. 
441. Additional data supplied by Turner relative to analysis B. 
Analyses by W. F. Hillebrand, record No. 1432. 
A. Metadacite, If miles southeast of Milton. Vulcanose. Contains 
quartz, feldspar, and hornblende. P. R. C. 777. 
B. Metadacite, 1£ miles northeast of Milton. Lasseiwse. Contains 
feldspar, quartz, epidote, chlorite, and iron ore, in a groundmass 
made up probably of feldspar and quartz. P. R. C. 752. 
C. Meta-andesite, li miles northward from Jenny Lind. Placerose. 
Contains quartz, plagioclase, epidote, and chlorite derived from augite. 
Si0 2 . 
FeA 
FeO... 
MgO 
CaO 
Na 2 
K 2 
H 2 Oatl00° .. 
H 2 above 100 c 
Ti0 2 
V,(h 
MnO 
SrO . 
BaO 
C0 2 . 
72. 24 
13. 84 
1 . 45 
1.86 
1.10 
3.40 
4.43 
.39 
. 17 
.69 
.41 
.10 
.12 
trace 
.08 
100. 28 
B. 
71.19 
13.81 
1.45 
1.68 
.74 
2.87 
4.24 
1.82 
.15 
. 92 
. 35 
.08 
.07 
trace 
.16 
.82 
100. 35 
61.37 
15. 41 
3.15 
3.89 
3.48 
4.42 
3. 76 
.34 
.29 
2.70 
.60 
.08 
.47 
trace 
.08 
100. 04 
11. TUOLUMNE COUNTY. 
Rocks collected by H. W. Turner, and partly described in his papers 
in the 14th and 17th Annuals. The latites were named and described 
by Ransome in Bull. 89. Some additional data have been furnished 
by Turner. 
A. Soda-syenite-porphyry, dike east of Moccasin Creek. Tuol- 
umnose. Consists mainly of albite, with a greenish mineral which is 
probably segirite. Analysis by H. N. Stokes, record No. 1563. 
P. R. C. 773. 
B, Augite-syenite, dike on Turnback Creek, about 1 mile north of 
Carter post-office. Highwoodose. Hitherto unpublished. Contains 
