366 Transactions of the State Agricultural Society. 



to the westward, through which, it is more than probable, that the Colo- 

 rado once flowed into Leath Valle}*, and from thence, through the chain 

 of lakes previously spoken of, to the Gulf of California. This locality 

 deserves further investigation, for the mind is irresistibly drawn to the 

 conclusion that the decadence of Arizona dates from the time when the 

 great Colorado had cut down its bed in the big canon so deep that its 

 course was diverted at Collville to a southerly direction, and the lakes 

 which once existed in Southern California, and were by it supplied, 

 gradually evaporated, to become the desolate sinks of insignificant 

 streams, or broad arid deserts. What the former influence of the lakes 

 was may be partially judged by the phenomena of both Winter and 

 Summer rains in the vallej's south of Salt Lake, which follow the lakes 

 between Sevier Lake and the great Salt Lake, and make a habitable 

 region in the midst of a desert. It is not unreasonable to conclude that 

 the Aztec civilization of Arizona, of w y hich there are so many traces, 

 was founded on a similar condition of things, perishing only when this 

 condition was destroyed. 



That the influence of these broad deserts is prejudicial may be further 

 seen in the gradually diminishing rainfall from Oregon to Southern Cal- 

 ifornia, and in the stoppage of the Summer rains of Sonora and Arizona 

 before they reach San Bernardino County, although the latter properly 

 belongs to the area affected by them. Again, the great amount of water 

 in the Colorado during the present Winter has caused a large overflow 

 in the desert through the channel of jSTew River, and San Diego has had 

 an abundant rainfall. May not this be the result, in part, of the dimi- 

 nution in the temperature of the desert, owing to the presence of large 

 bodies of water on the lower Colorado? 



These are merely suggestions, but they are worth consideration. 



Yours, very respectfully, 



RICHARD H. STRETCH. 



