COLORADO IRRIGATION WATERS AND THEIR CHANGES. 9 
tect nothing favoring the assumption of the formation of zeolites in 
this manner. The general trend of the evidence is that there is a 
greater similarity'to the conditions existing in veins than to those 
conditions where zeolites are formed. The theory of the existence 
of zeolitic constituents within the soil is convenient for many rea¬ 
sons, but it is doubtful whether it is correct for all soils, if it is for 
any. 
§ 18. In Bulletin No. 65 I have shown to how great an ex¬ 
tent onr soils are made up of felspar particles, and have also held 
that they owe their origin to the disintegration of the granites and 
gneisses of the Front or Colorado range. It clearly follows that 
the present rivers or the streams which they now represent, have 
contributed in the past, as they are now doing, to this work. The 
contribution made by the Poudre being, according to the assump¬ 
tion previously made, 320 cubic feet of solid rock taken into solu¬ 
tion daily from the area of 1,050 square miles. This result is en¬ 
tirely apart from its mechanical action by which a manifold greater 
mass is broken down and moved from one place to another. It 
may not be removed very far, but it is on its way to a new resting 
place. 
§ 19. The statement that the clear water of the river which 
we are accustomed to think of as pure snow water, is daily carrying 
not less than twenty-six tons or 320 cubic feet of solid rock from 
the mountains down to the plains, is so large that it will undoubt¬ 
edly strike the average person as over-estimated. But such is not 
the case, for by direct experiment we have succeeded in bringing 
into solution a little more than twice the amount per gallon as¬ 
sumed to be present in the calculation. 
§ 20. Finely powdered felspar was taken and treated for four¬ 
teen and one-half days with water and carbonic acid, and we found 
that the solution had dissolved out of the felspar constituents equiv¬ 
alent to 4.53 plus grains per gallon, and this amount, 4.536 grains, 
would not be considered a large quantity of mineral matter to be 
found, even in the water of mountain streams. This would give 
us rather more than double as much, or 640 cubic feet per day in¬ 
stead of 320, as previously assumed. The aggregate removed, 
whether it be measured in tons or cubic feet, is a considerable quan¬ 
tity. The range of total solids contained in the Poudre water is 
from 2.6 grains to 4.6 grains; in other words, assuming a flow of 
300 second-feet, the amount actually removed daily lies between 
320 and 640 cubic feet of rock material weighing about 26 tons for 
the lower figures or 52 tons for the higher. 
THE SOURCE OF THE MATERIAL. 
§ 21. I have alluded to the felspar as the source from which 
the water obtained its mineral matter in this case. It is not in- 
