SOIL OF THE DESERT—AGRICULTURAL CAPABILITIES—IRRIGATION. 249 
same composition as the alluvial bottom-land of the Colorado, which is covered with a growth 
of mezquite, cotton-wood, willows, and grass. Goodcrops of corn, beans, and melons are also 
raised by the Yuma and Cocopas Indians. The river-bottom of the Gila is said to be adapted 
to the growth of cotton—it being cultivated by the Pimo Indians, who have long been known 
to manufacture cotton blankets. Other evidences of the fertility of the clay, when moistened, 
are presented by the vegetation on the borders of the lagoons, and on the banks of New River, 
which are said to be covered with a dense growth of grass. It is, in part, for the use of this 
grass that the emigrants prefer the trail along the stream to the shorter one, under the sand- 
hills, by Cooke's Well and Alamo Mocho. 
The Cohuilla Indians, in the northwestern part of the Desert, raise abundant crops of corn, 
barley, and vegetables in the vicinity of the springs at their villages. We also observed a 
dense growth of weeds over a wide area near the mountains, but not far from the cultivated 
fields. The ground upon which they grew was moist and miry, being supplied with 
water by numerous springs. The barley-field found near the sand-hills, at the base of the 
Bernardino Pass, was upon the clay of the Desert; the thickness and size of the stubble was 
such as to indicate a large yield. 
The specimens of the soil near the Cohuilla villages, which were procured for analysis, are 
rich in all the mineral ingredients necessary to fertility. Theexamination of the sample showed 
the presence of the following substances : 
Soluble in water. Soluble in acid. 
Alumina and oxide of iron. ilica. 
Lime. Clay and oxide of iron and manganese. 
Magnesia. Carbonate of lime. 
Soda, (abundant.) : Magnesia, (unusually large.) 
Potash, (abundant ) Phosphoric acid. 
Phosphoric acid. Sulphuric acid. 
Sulphuric acid. Soda. 
Chlorine. Potash. 
Organic matter. 
The per-centage of the sand, organic matter, carbonate of lime, and the soluble salts was 
determined by weight with the following result :1 
Sand 60. 00 per cent. 
Carbonate of lime i 16.59 per cent. 
Organic matter ..- 1. 30 per cent. 
Soluble in water..... 1. 58 per cent. 
This may be called an exceedingly rich soil, and is adapted to various crops. The large 
amount of carbonate of lime is due, in part, to the presence of the small shells distributed 
through the soil. "The amount of organic matter, though not by any means very small, would 
be rapidly increased by cultivation. 
From the preceding facts it becomes evident that the alluvial soil of the Desert is capable of 
sustaining a vigorous vegetation. The only apparent reason for its sterility is the absence of 
water, for wherever it is kept moist vegetation springs up. If a supply of water could be 
obtained for irrigation, it is probable that the greater part of the Desert could be made to yield 
crops of almost any kind. During the seasons of high water, or the overflows of the Colorado, 
there would be little difficulty in irrigating large areas in the vicinity of New River and the 
lagoons. By deepening the channel of New River, or cutting a canal so low that the water of 
the Colorado would enter at all seasons of the year, a constant supply could be furnished to the 
1 See Appendix, Article VII, Chemical Examinations. 
32 F 
