ORIGIN AND USE OF NATURAL CIAS AT MANITOU. 29 



All the circumstances, therefore, connected with the posi- 

 tion and flow of the springs, and the mineral contents of the 

 water, etc., etc., seem to be consistent with, if they do not 

 favor this explanation. 



Briefly, then, the theory advanced of the origin of the 

 natural gas at Manitou may thus be summarized: Water 

 percolating through silicate rocks and becoming highly min- 

 eralized under favorable conditions of temperature and pres- 

 sure, makes its way through cracks and profound rock-fissures 

 by the action of gravity and the ascensional power imparted 

 by heat, to the limestones west and north of Manitou. It is 

 here increased in volume and in dissolved salts by the numer- 

 ous additions of seepage waters from the local rocks, and also 

 lowered in temperature at the points where these influxes occur. 

 By chemical reactions some of the dissolved salts are changed, 

 and the carbon dioxide originally held (almost entirely) by 

 the limestones is liberated from that combination but dis- 

 solved in the w^ater on account of the great hydrostatic pres- 

 sure. As the waters rise throjigli the irregular channels 

 enlarged from cracks and seams, the pressure decreases, and 

 more and more of the dissolved gas escapes from the water, 

 until at last when the surface is reached at the various springs 

 the gas emerges with the rythmic flow due to the irregulari- 

 ties in the channels of exit. 



Of the many temptations to comparisons and generaliza- 

 tions growing out of his study upon the origin of the natural 

 gas at Manitou, the writer yields to the two following: (1) The 

 caverns at Manitou mark the scene of a former considerable 

 chemical activity, possibly induced by the same causes now 

 at work in the lower strata in the manner mentioned above. 

 If the theory advanced in this paper is true, caverns of like 

 kind may now be in process of excavation which will in time 

 rival or eclipse those so much admired in the now drained 

 and fragmentary parts of strata on the west side of Williams' 

 canon. (2) The data in the hands of the writer concerning 

 the carbonated mineral springs of other localities are too 

 meagre to permit of any very general comparisons or deduc- 

 tions, but it would appear from published descriptions that 



