SOUTHERN PACIFIC LINES 153 
Simon. Its width averages about 6 miles. There is also a small, 
narrow area:of artesian flow at the San Simon Ciénega (se-ay’nay-ga) 
a few miles up the valley, and an extensive area in which water is 
obtained by pumped wells of moderate depth. Up to 1910 the region 
was a range for cattle belonging to widely separated ranches using 
water from shallow wells. Then the discovery of water in deeper 
beds under sufficient head to afford artesian flow brought many 
agriculturists, who have utilized the water for irrigation. In 1914 
there were 127 flowing wells, mostly ranging in depth from 500 to 
1,000 feet and yielding from 20 to 100 gallons a minute. It was 
estimated that at that time the total flow approximated 15 second- 
feet, or 11,000 acre-feet a year. Many nonflowing wells are now 
pumped. The quality of the water is excellent, most of it containing 
only from 250 to 380 parts per million of total solids. The moderate 
supply of water requires careful conservation, especially to avoid 
waste. The water occurs in gravel interbedded in light-colored 
clay and sand, which have been penetrated to a depth of 1,230 feet. 
These beds are overlain by a thick body of blue clay which holds the 
water down. The source of supply is rain that falls on the sides and 
upper part of the valley. The region has an arid climate, with a 
ean annual precipitation of less than 7 inches at San Seine: at 
Bowie, however, it is nearly 14 inches, a difference probably due to 
the proximity of the Dos Cabezas Mountains, in which the precipita- 
tion is estimated as near 20 inches. At Paradise, in the Chiricahua 
Mountains, it is 18 inches. 
Originally the San Simon Valley was grassy, and the broad flats were 
covered with a coarse, high grass known as sacaton (sa-ca-tone’). 
With the extension of cattle grazing this was largely eaten out, but in 
rainy seasons the lower parts of the area had considerable small grass, 
and grama and other grasses grew in fair supply on the higher slopes. 
Since the advent of settlers erosion has cut deeply into the valley 
bottom, and many wide gullies and bare areas have resulted. 
In the west slope of the Peloncillo Mountains, about 10 miles north- 
east of San Simon, are very small deposits of ‘‘saltpeter,” or potassium 
nitrate, in rhyolite tuff, which have been prospected to some extent. 
It has been found, however, that the material is only a surface im- 
pregnation in crevices and under overhanging cliffs. Probably it has 
been formed through the action of bacteria on organic matter in places 
where the air has access and where the associated rock is sufficiently 
porous to permit the percolation of water, which would be concentrated 
by evaporation. The mineral occurs in this manner in many caves 
and places protected from the rain wash in the West and generally 
gives rise to the false hope that valuable nitrate deposits may be found. 
The Chiricahua Mountains, which culminate in the peak known as 
Cochise Head (elevation 8,100 feet), are 15 miles south of San Simon, 
’ Pes wre ent 
