CHEMICAL ANALYSES. 185 
Phosphoric acid. .07 
Chlorine. .37 
Vegetable matter.. 1.60 
Moisture and loss. 3.00 
100.00 
9. SOIL FROM PIMAS PLAINS. 
Silica. v ... 83.24 
Alumina. 7.00 
Peroxide of iron. .78 
Oxide of manganese.. .11 
Lime. 1.88 
Magnesia. .67 
Potass.. .37 
Soda. 41 
Carbonic acid... 1.27 
Sulphuric acid. .21 
Phosphoric acid. .04 
Chlorine. .28 
Vegetable matter. 1.24 
Moisture and loss. 2.50 
100.00 
10. SOIL FROM DESERT SOUTH OF PIMAS VILLAGES. 
Silica. 89.26 
Alumina. 6.40 
Peroxide of iron. .87 
Oxide of manganese. .15 
Lime. .44 
Magnesia. .33 
Potass. .66 
Soda. .42 
Carbonic acid... 
Sulphuric acid. .10 
Phosphoric acid. .03 
Chlorine.;... .30 
Vegetable matter. 
Moisture and loss. 1.44 
100.00 
These soils have one common source, a decaying, felspar granite rock. The fragments of 
lartz are rounded and semi-transparent, intermingled with minute crystals of white felspar 
id brown colored mica; small particles of amphibole may be seen through the soil when 
24 U 
