26 



UNITED STATES AND MEXICAN BOUNDARY. 



towards the sources of the streams or from local springs, were often of great length and magni- 

 tude. The one belonging to the San Diego mission, for instance, is a continuous wall of 



for the distance of nearly three miles. The upper portion of each valley was generally 



masonry 



mam mission 



agricultural resources of the valley. 



In rec'ard to the eastern slope of the mountain hut little additional need he said. In the 

 immediate vicinity of the summit ridge arable land is found, but the more precipitous slope 



imi 



ed in extent to claim much attention. Desert valleys and pent up canons 

 succeed between this and the great plain. As far as all agricultural purposes are concerned 



mere 



and destitute of every kind of vegetation. 



We have already noticed that several shrubs are peculiar to this tract, which, if they serve 

 no other purpose, at least afford relief to the eye. 



seem 



limited cultivation of maize, beans, pumpkins^ and melo 



ram ma 



seem 



might b 



raised here. 



mi 



struction of artificial reservoirs and ditches. Still we must admit that any system of cultr 



must be very precarious in a location where its success depends upon such variable causes. 



The remarks respecting "New Kiver" apply in a great measure to the 



Colorado. Here 



v.Liii,i,«vx^^ xo, V,. ..^^^^^..j , jonfined to those portions of the valley that are subject to overflow and 

 the conseq^uent deposition of fertilizing sediment. The higher adjoining lands, being without 

 the reach of these influences, are, from their extreme aridity and the light porous nature of 

 their soil^ quite unfit for any cultivation. 



All the Indian settlements upon the Colorado with which we are acquainted are located with 

 reference to an overflowed portion of the river margin. Near the junction of the Gila with this 

 river one Indian village occupies an old river bed^ which, when the river is high, is completely 



* 



covered by the stream. Another settlement is situated upon a low alluvial delta lying between 

 the two riversj and a third is built in a slough. These are also flooded at high water. The 

 articles cultivated by these Indians are principally maize^ beans, and pumpkins. No doubt 

 that cotton, sugar, and many of the sub-tropical fruits would succeed here, but our present 

 knowledge respecting the extent of arable soil, of the vicissitudes of the climate, and of the 

 character of the different seasons, is too vague to warrant any but the merest conjecture in regard 

 to its future agricultural importance. 



