102 



DOUGLAS — RECORD OF BORINGS. 



[Nov. I, 



GRAVEL&CLAY 



QUICKSAND. 



MUTE CLAY. 



RED CLAY. 



BROWN CLAY. 



RED CLA Y. 



BROWN CLAY. 



subterranean reservoir in the basin-shaped valley, which has a very 

 gentle fall to the south, and therefore discharges some of its water 

 contents, by the subterranean stream of the Agua 

 Prieta, into the headwaters of the Yaqui river. 

 The water in abundance is struck at from nine to 

 thirty feet below the surface almost anywhere in 

 the trough of the valley ; and experiments ex- 

 tending over three years showed that ten acres of 

 fruit trees can be irrigated by twenty-foot wind- 

 mills, provided adequate reservoirs are provided. 

 If, therefore, a valuable product, such as fine 

 fruits, could be raised under the climatic condi- 

 tions prevailing, the question of power for arti- 

 ficial irrigation may be regarded as solved. The 

 attempt, however, to cultivate semi-tropical fruits 

 failed, principally through the extraordinary vari- 

 ations of temperature. 



During the term of the experiment a ther- 

 mometrical record was kept on the ranch, which 

 is printed below in parallel columns with a record 

 for the same period kept at Bisbee. This mining 

 town is situated in a deep ravine in the Mule Pass 

 Mountains, which flank the Sulphur Spring Valley 

 on the west, 1200 feet above the level of the val- 

 ley, but where, despite the higher altitude, the 

 diurnal variations in the annual experiments are 

 less than in the valley itself. These great sandy 

 valleys in the Southwest, covered at best with a 

 scanty growth of mesquite, and during the greater 

 part of the year by scorched grass, permit of such 

 rapid radiation through the cloudless heavens, 

 that the burning heat of the day falls, immediately 

 the sun sets, to a temperature which is sensibly 

 chilling, and which therefore has a seriously 

 detrimental influence on delicate vegetation. 

 Were these vast valleys simultaneously cultivated 

 and clothed with verdure, this climatic obstacle 

 to agriculture would be reduced, as is the case 

 in the Salt River Valley, where an area of large 

 enough extent is under cultivation to almost relieve the rancher 



M 



+35\ 



GRAVEL&CLAY 

 SAND ROCK. 



GRAVEL. 



CRAVEUCLAY. 



tw 



480'< 



RED CLAYS SAND 



RED CLAY 



ize 



7653JE 



SECTION — DIAMOND 

 DRILL HOLE INTHESUL- 

 PHUK SPRING VALLEY, 

 ARIZONA. 



