THE NONMKTALLIC MINERALS. 



479 



mctooric. that, is, it is wutor wliit-li has FaUcn upon tlic earth from 

 clouds, and iJ-radually iK'rcohitinjjr downward issues again in tii(> form 

 of sprino-s at lower levels. In this passaoe through the superficial 

 portion of the (>arth\s crust it dissolves the various salts, the kind and 

 quantity l)eing- dependent upon the kind of rocks, the teinperatui-es 

 and pressure of the water, as well as the amount of absorbed gases it 

 contains. 



lioth the mineral contents and the temperature of spring waters are 

 dependent upon the geological features of the country they occupy. 



As a rule springs in regions of sedimentary rocks carry a larger 

 proportion of salts than those in regions of eruptive and nu^tamorphic 

 rocks. Thermal springs are as a rule limited to regions of compara- 

 tive recent volcanic activity, or where the rocks have been disturbed, 

 crushed, folded, and faulted, as in mountain<nis regions. Occasional 

 thermal springs are met with in undisturbed areas, but such are 

 regarded as of deep-seated origin, and to owe their temperatures to 

 the great depths from which they are derived. 



Dhtr'tlnithm. — Mineral springs of some sort are to be found in each 

 and all of the States of the American Union, though naturally the 

 resources of the more sparsely settled States have not as yet been fully 

 developed. For this reason the table given herewith is to a certain 

 extent misleading: 



Produclion of mineral ivaters in 1890 by Stales and Territories. 



State or Territory. 



Alabama 



Arkansas 



California 



Colorado 



Connecticut 



District of Columbia 



Florida 



Georgia 



Illinois 



Indiana 



Iowa 



Kansas 



Kentucky 



Maine 



Maryland 



Massachusetts 



Michigan 



Minnesota 



Mississippi 



Missouri 



New Hampshire 



New Jersey 



New Mexico 



