ORIGIN AND USE OF NATURAL GAS AT MANITOU. 21 



from the Hiawatha springs. It is very probable that 

 percolating waters from the streams or from local 

 seepage channels, make their way into the springs — 

 such intlux being greater in some springs and smaller 

 in others. In the Ute Iron spring calcium and mag- 

 nesium are Tow, and silica, chlorine, iron, sulphuric- 

 anhydride, soda and potash relatively high. The prox- 

 imity of this spring to the silicate rocks on the south, 

 and to the very broken silicious silurian limestone and 

 Cambrian quartzites on the north and west, suggest 

 reasons for a possible change in this spring water, on 

 the supposition that its main source is the same as 

 that yielding the waters of the other groups. 



3. The presence of so large quantities of the bicarbonates of 



calcium and magnesium points to a prolonged contact 

 of the waters with the limestones. 



4. The almost total absence of iron salts indicates either a 



source quite free from ferruginous minerals, or more 

 probably the oxidation of dissolved iron and its 

 previous precipitation as hydrated sesquioxide by the 

 carbonated alkaline matters with which it comes in 

 contact as the waters move toward the springs. 



5. The high percentage of chlorides may be derived from 



the Silurian rocks or with less probability from the 

 more distant juratriasic beds, since no saline deposits 

 in them are known in this vicinity. 



f). The large percentage of sodium bicarbonate probably in- 

 dicates an origin among silicate rocks, whence the soda 

 (and potash) may come as carbonates formed by the 

 decomposition of the rocks by atmospheric waters con- 

 taining carbonic acid, or as alkaline silicates, which 

 react upon the limestones (calcium carbonate) before 

 reaching the surface. 



7. The sulphates may come from unseen gypsum beds such 

 as are found two or three miles away, and lower down 

 the Fountain creek, but it is more probable that they 

 come in greater part at least from the oxidation of 

 sulphides in granites, igneus rocks or even sedimentary 



