1901.] DOUGLAS — RECORD OF BORINGS. . . 161 



RECORD OF BORINGS IN THE SULPHUR SPRING VAL- 

 LEY, ARIZONA, AND OF AGRICULTURAL EXPERI- 

 MENTS IN THE SAME LOCALITY. 



BY JAMES DOUGLAS. 



(Read November 1, 1901.) 



The Copper Queen Consolidated Mining Company has since 

 1880 worked extensive copper deposits in what are probably car- 

 boniferous limestones, lying on the eastern flank of the Mule Pass 

 Mountains, in Cochise county, Arizona, within a few miles of the 

 Mexican boundary and 5700 feet above the sea. The geology of 

 the region east of the Mule Pass Mountains renders it probable that 

 there are Jura-Triassic strata lying unconformably over the carbon- 

 iferous limestones, and that within the Jura-Triassic there may occur 

 coal. Where coal occurs in Northern Sonora, to the south of the 

 great Sulphur Spring Valley, and in Arizona, to the north of that 

 valley, the beds are so shattered by intrusive rocks as to detract 

 largely from their commercial value. But beneath the broad Sul- 

 phur Spring Valley we considered it possible that there might be 

 undisturbed coal beds of sufficient extent to warrant their exploita- 

 tion. With the object of determining this, the Copper Queen 

 Company drove a diamond drill hole in the trough of the valley. 

 The attempt was abandoned before solid rock was reached. The- 

 diamond drill penetrated the alluvium, as shown by the following 

 record of borings, for 765 feet without reaching solid rock. The 

 record is interesting as showing the extent of erosion and the 

 depth to which the valleys are filled by detritus in the arid 

 region. 



At the same time, the Copper Queen Company, being anxious to 

 develop every possible industry in connection with their mines, 

 and as a feeder of their railroad, instituted some systematic agricul- 

 tural experiments on a tract of land lying in the trough of the same 

 Sulphur Spring Valley. The valley extends in a general north-and- 

 south direction for about one hundred and twenty miles, and, with 

 very gradually sloping sides, has an average width of about twenty 

 miles. It is surrounded to the north, east and west by high arid 

 mountain ranges, on which the average annual rainfall is ten inches. 

 While a certain pr.oporlion of this moisture escapes by evaporation, 

 the larger portion sinks through the porous soils and collects as a 



