184 
CHEMICAL ANALYSES. 
TRACHYTE CANONS OF GILA RIVER. 
Specific gravity, 2.64. 
Silica. 57.15 
Alumina. 16.90 
Oxide of iron. 8.50 
Oxide of manganese. .04 
Magnesia... 1.86 
Lime. 6.40 
Potassa. 3.80 
Soda. 1.10 
Water. 3.28 
99.03, in 100 parts. 
6. ARGENTIFEROUS GALENA, ORGAN MOUNTAINS, WEST SIDE, STEVENSON’S 
MINE. 
Specific gravity, 7.8. 
Lead. 86.40 
Sulphur. 13.34 
Silver. ,16 
Manganese. .20 
100.00 
7. ARGENTIFEROUS GALENA, EAST SIDE OF ORGAN MOUNTAINS, FORT MINE. 
Specific gravity, 7.75. 
Lead. 86.00 
Silver. .17 
Sulphur. 13.36 
Manganese and antimony. .67 
100.00 
8. SOIL, EIGHT MILES EAST OF FORT YUMA, CAMP ON GILA. 
Silica. 81.22 
Alumina. 8.00 
Peroxide of iron... .67 
Oxide of manganese. .07 
Lime. 1.15 
Magnesia. .71 
Potass. .84 
Soda. .76 
Carbonic acid. 1.00 
Sulphuric acid. .54 
