38 Colorado Experiment Station 
plagioclase as is also that of river water flowing' over sands and boul¬ 
ders of granitic origin. This character is very marked in the two ar¬ 
tesian waters given as typical of the white artesian waters of the valley. 
Here we find that, approximately, one-third of the total solids 
consist of sodic carbonate, with relatively large quantities of silicic 
acid and calcium salts. The latter substances are practically removed 
from the brown waters. The river waters show the same fact, only to a 
less marked degree, ana the elimination of the silicic acid and alkaline 
earths has not taken place. In the spring waters we find the same fact. 
In the water from the Washington Spring,s, for instance, we find a 
total of 5.7 grains of solids in an imperial gallon, of which, 1.74 grain 
is silica, 2.85 grains are alkaline carbonates and 0.98 grain is sulfates 
of the alkaline earths. 
This process of taking sodic carbonate into solution from the 
plagioclase felspars is going on at this time and the only adverse 
question attaching itself to this view of the origin of the sodic carbo¬ 
nate is in regard to its sufficiency, of which I think there can be no 
reasonable doubt. The carbonate of calcium has been deposited in 
the form of small concretions and the silica may have been used 
in a variety of ways, perhaps to enlarge sand grains or to form new 
silicates. I have no knowledge of any direct proof that this latter 
process is going on. In the case of the Cache la Poudre water 
we find the whole of the silica removed on its first contact with the 
conditions that obtain in its plains section. It seems probable that this 
disappears in the formation of new silicates. 
The origin of the carbonates here suggested is in harmony with 
the facts that we find obtaining in regard to the action of water on 
these plagioclase felspars, also with the composition of the artesian 
waters themselves. It is immediate and simple, and is suggested by 
the facts in the case. 
LARGE AMOUNTS OF SODIC CARBONATE POURED ONTO LANDS 
BY WELLS 
In order that the general reader may form some appreciation of 
the amount of sodic carbonate involved in this question, let us suppose 
that the “Soda Well” discharged 200 gallons a minute and that it car¬ 
ried 97 grains to the gallon. Such a well would deliver 5^4 tons 
anhydrous sodic carbonate a month, or more than 12 tons of wash¬ 
ing soda. Some of these wells have been flowing for 20 years, others 
even longer. It is true that many of these wells are only 2, 3 and 4 
inches in diameter, but there are many of them, and the amount of 
soda yielded during the past 25 years must have been considerable. 
I offered, 20 years ago, to furnish a complete analysis of any 
sample of black alkali found in this State without charge. I excepted 
