ARTESIAN WATERS IN THE ARID REGION. 601 



and availability of underground waters, for not only have large 

 sums been wasted in boring in unfavorable localities, but imprac- 

 ticable notions have been obtained from scientific treatises on 

 this subject. 



The laws of the distribution and utilization of underground 

 water are as simple as those controlling the surface supply, but 

 the popular fallacies concerning them are appalling. The most 

 prevalent of these is that the waters originate at some remote 

 point from their outlet, and flow in subterranean streams like the 

 " blood in the human body," as a farmer once said, and that these 

 streams must be tapped by the well borer or digger before water 

 can be obtained. In nearly every community is some person sup- 

 posed to possess the art of locating the exact spot above these 

 currents by means of a switch called the divining rod. It is also a 

 current fallacious belief that all underground water is due to rain 

 which falls on the more or less distant mountains, and especially 

 is this true in the region between the Rocky Mountains and the 

 Mississippi, where every spring and well, even on the Texas 



Fig. 2. — Favorable Structure for Artesian Water, in which the Receiving Area is a 



Valley. 



coastal plain a thousand miles distant, is commonly explained 

 upon the hypothesis that the water comes from this lofty range. 



These prevalent impressions in the minds of those untrained in 

 geology are more excusable than the widely prevalent idea con- 

 veyed by cuts in geological text-books that the usual and ordinary 

 conditions for artesian wells are in great synclinal areas in which 

 the strata can be seen markedly dipping from two including 

 mountain borders against which their edges are upturned as 

 shown in the following figure. 



While there is no theoretical objection to this ideal conception, 

 the conditions it represents seldom occur in Nature ; on the con- 

 trary, as will be shown later, mountain rocks are not the source 

 of great artesian wells ; neither do they usually occur in synclinal 

 valleys, but the most favorable conditions are gently sloping 

 monoclinal plains in which the receiving areas, instead of being 

 the upturned mountain rocks, are, in fact, the escarpment valleys 

 of the plains. (See Fig. 2.) 



To understand the distribution of earth water, it is necessary 

 to be familiar with the true laws of its occurrence. The rainfall 

 is the source of all underground water, and with the exception of 



