IGNEOUS AND CRYSTALLINE ROCKS. 77 
2. BUTTE DISTRICT. 
Rocks received from W. H. Weed and G. W. Tower. Some of the granite rocks are 
described by Weed in Jour. Geology, vol. 7, p. 737. 
A. Butte granite. Amiatose. A quartz monzonite, variety banatite, from Walker- 
ville Station. ‘Contains quartz, andesine, orthoclase, hornblende, and biotite, with 
a little titanite, apatite, and magnetite. 
B. Biotite from A. 
C. Amphibole from A. 
Analyses A, B, C, by H. N. Stokes, record Nos. 1686, 1808. 
D. Butte granite, Gagnon mine, Butte. Amiatose. 
E. Butte granite, Atlantic mine, Butte. Harzose. 
F. Butte granite, Alice mine, Butte. Harzose. Analyses D, E, and F, by W. F. 
Hillebrand, record No. 1692. Mineralogically the rocks are like A and D. 
A B Cc Dz E. F 
64.05 | 64.34 63. 87 
15.38 | 15.72 15.39 
2.20 1.62 1.93 
2.74 2.94 3. 08 
2. 08 2.17 2.23 
4.30 4.24 4.30 
2.74 2.76 2.76 
4.00 4.04 4.18 
+27 +25 -19 
- 83 +76 - 69 
- 60 -53 - 65 
(2?) - 02 - 03 
+35 - 03 -15 
The six following analyses represent alterations of quartz monzonite, the so-called 
Butte granite: : 
G. Weathered Butte granite. 
