SOURCE OF AQUEOUS SOLUTIONS. 1067 



origin. Numerous large springs are found both in regions in which there 

 has been no igneous action for a long time and in regions in which vol- 

 canism is now or has been recently prominent. No one would claim that 

 in regions of the former class the water is of other than meteoric orig'in. 

 For instance, no one would hold that the waters of the great springs of 

 the Appalachians and the Mississippi Valley are derived from any other 

 source. Why then should this be held in reference to the Cordilleran 

 region of the West"? He who maintains that the water for these springs 

 is largely derived from igneous rocks must show that the amount which 

 issues is greater than could be expected upon the meteoric theory, taking 

 into account the precipitation, the climate, the character of the rocks and 

 the topography. The only way to find the effect of an agent, such as 

 igneous rocks, with reference to the water is to compare regions in which 

 these rocks occur with others in which they are absent. Making this com- 

 parison, observation has as yet not shown a difference of volume, but in 

 regions of volcanism the waters issuing from springs are frequently hot, 

 and are depositing more than an average amount of mineral material. 

 This difference is therefore logically referred to the igneous rocks. During- 

 its underground journey the water comes into contact with or comes 

 near to hot rocks, and thereby becomes heated. In consecpience of this 

 it becomes a far more potent chemical agent, and takes into solution a large 

 amount of mineral matter. When gathered into and rising in trunk 

 channels a considerable portion of this mineral matter is deposited. This 

 effect may be accentuated in volcanic regions by mechanical action. As 

 has been pointed out in other places, the deposited material is derived from 

 all the rocks with which the underground water comes into contact during 

 its journey, but in many cases the material is dominantly derived from a 

 single formation or series through which the water journeyed. 



While it is held that the water is dominantly of meteoric origin, in 

 regions of volcanism where magmas are crystallizing the heated solutions 

 have doubtless had accretions from this source. But those who hold that 

 the enormous quantities of water issuing from hot springs are mainly 

 derived from crystallizing magmas must furnish the evidence in favor of 

 excepting them from the general rule. The fact that cold springs issue 

 adjacent to hot springs has no bearing on the case, for often trunk' channels 

 which issue close together have entirely different feeding areas. Nor is the 



