26 COLORADO COLLEGE STUDIES. 



still sufficient lient to cause the water to dissolve its large 

 percentage of mineral matter, occurred in this immediate 

 neighborhood. Altogether, in the absence of some positive 

 evidence of the j^resence of such heated rocks this explana- 

 tion must be quite doubtful. 



It remains then to discuss the probability of the formation 

 of this gas by chemical reaction of dissolved substances in a 

 flow of water which reaches the limestones of Manitou, and 

 to examine whether there are at hand sources whence this 

 saline solution might reasonably be expected to come. This 

 explanation differs from the preceding one mainly in that the 

 source of the reacting salts is more remote. Is there such a 

 source of active chemical solutions present at Manitou, and 

 if that be asserted, what evidence can be adduced in support 

 of a theory of this sort? It must be admitted that positive 

 proof is not now attainable, but there are some considera- 

 tions which may be urged in favor of such a theory. 



Reference has already been made to the faults and rock- 

 slips at Manitou, and to the probability of the presence of an 

 extensive and profound rock-fissure extending from Manitou 

 continuously along the general line of the Ute Pass up into 

 Manitou Park. In view of the presence of an extensive out- 

 flow of igneus rocks not many miles distant at Cripple Creek, 

 and of an outcroj) of phonolite nearer still on the south side 

 of Pike"s Peak, it is altogether likely that a deep fissure such 

 as that at Manitou, if not in some way connected with those 

 disturbances and the loss of interior liquid matter under this 

 region, yet penetrates to depths strongly affected by these 

 heated zones. If a fissure occurs at Manitou which penetrates 

 the earth's crust sufficiently to reach highly heated rocks, the 

 natural action observed in fissure-vein filling will be very 

 actively induced, and highly mineralized solutions will result 

 as before explained. And if further the fissure at Manitou 

 extends to Manitou Park or communicates with fissures of 

 the Cripple Creek district or with those in some other 

 elevated region, the waters which everywhere find exit in 

 such rock crevices, would, in seeking their level, according to 

 physical laws, naturally emerge at the lower point where the 



