Bisbee daily review., 1906-08-26

examination was made of the artesian basin near Benson. The majority or the settlers of tha region have been in the valley but a short time.'
 The valley is situated in the midst of a mining region of considerable i'm portance and the demand for agricul- tural products far exceeds the possible supply Nearly all produce is ship ped in from a distance, and high prices prevail. The development of water in this valley would therefore create a community of small land own CT resident on their land and at the same time materially benefit the i'm portant mining interests of the region.
 The San Pedro Valley is situated between the Galiuro, Dragoon, Bisbee and Tombstone Mountains on the east and the Huachuca, Whetstones, Rim con, and Santa Catalina Mountains or the west. From these mountains many side streams enter the valley. Most of them sink beneath the sur face before reaching the San Pedro but a few reach that stream. The San Pedro has a continuous surface flow. although the volume is small during the dry season. ..
 The valley was examined from Ben son to a point about eight miles south of Fairbank. a distance of 2S miles. This part of the valley broadens about three miles north of Fairbank, the fragmentary material becomes finer, and from this point to Benson and be- yond, the valley fill is prodominantly a dull red clay to a depth of about 5000 feet. beneath which is coarser material to about 300 feet, the depth of the deepest wells.
 It is in this region that the wells described below are situated.
 The valley floor is composed of two distinct divisions, the alluvial bottom lands bordered by bluffs 60 feet high and the mesa lands rising gently from the bluffs to the bordering hills. The bottom lands slope gently from the bluifs to the river and are composed of fine silt and clay with little sands. The mesa lands are carved into bad land structure" near the bluffs, but back short distance the surface is comparatively even.
 The material of the valley fill is un- consolidated sand, gravel, clay, and cement, the clay greatly predominant ing. The bluffs are generally capped with gravel beds several feet thick. Below the gravel are alternating lay
 
 cemented.
 In many pie res the clay contains gravel which is irregularly distribut- ed and varies in size, the largest peb- bles being several inches in diameter.
 Where the bluffs were closely exam. ined a band of white cement about three feet thick was found. The rec ords of wells indicate that the mater ials to a depth of over 900 feet is similar to that seen in the bluffs.
 In the San Pedro Valley, and ir other parts of the Southwest, there have been several stages of erosion and accumulation.
 Considering only the material form ing the present valley fill, it is evi- dent that a broad deep valley was ex- cavated in the older rocks, then this valley was filled with sand and clay to the elevation presented by the mesa and in these deposits was car ried secondary valley, which was small compared to the original valley. The secondary valley was then partly filled, the condition at the present time.
 There are over 200 wells in the San Pedro valley, between Benson and Fairbank, distance of 20 miles. They are owned by about 45 men. The wells were all bored and vary from ; l 1-2 to inches in diameter( with the exception of the railroad weIls).
 Some are cased only few feet, and the best are cased to a depth of about 400 feet
 Tn 1900 two 10-inch wells-707 and sos feet deep-were bored at Benson for the s. P. Co. Water was strucsS at depth of 800 feet and flowed at iae rate of 42 gallons per minute.
 The flow was not increased by the additional depth. A satisfactory amount of water was obtained by pumping and the boring was discon- tinued.
 The pumps discharge 47,00O,000 gal Ions during each month, CT an aver age of about 109 gallons per minute. When the pumps arc not il operation the water flows slowly from the top of the wells. When working at the regular rate the pumps lower the water to depth of 50 feet below the surface. A careful log of all tho wells was kept by the engineer and is given herewith as follows:
 Surface soil. .. .. .... .. 10 feet San and gravel. .. .......- 110 feet e.