A i, kalui In Colorado 
37 
ANALYSIS OF GROUND-WATER NO. 490 
Calcic sulfate . 
Calcic carbonate. 
Magnesic carbonate . 
Magnesic chlorid . 
Magnesic silicate . 
Potassic silicate . 
Sodic silicate . 
Aluminic and ferric oxids 
Ignition .. 
Percent 
55.647 
15.081 
0.577 
11.809 
3.233 
0.377 
8.441 
0.075 
(4.760) 
Total 
100.00 
A\ e ha\ e a number of other analyses of alkalis from this section 
and they aie all of this type with few exceptions. These exceptions 
belong to the chlorid type. But to undertake to discuss types of alkalis 
in this place would lead us away from our purpose and tend to con¬ 
fusion rather than to clarity. The reader should remember, however, 
that the paiticular form of alkali with which he has to deal may be 
produced in his particular district by the interaction of the common 
salts occurring in the soil of the section. Sometimes these sections or 
areas are quite small. 
SODIC SULFATE PREVAILING ALKALI IN ONE AREA OF 1,000 
SQUARE MILES 
The statements made in the preceding apply to an area of probably 
more than 1,000 square miles of which it is perfectly safe to state that 
the prevailing alkali is sodic sulfate associated with more or less calcic 
and magnesic sulfate. I have a number of analyses of alkalis from this 
section that contain from 90 to 96 percent of sodic sulfate. This type 
of alkali does not contain much sodic chlorid. I think I have given 
about the highest that we have found, i.e., 15 percent of the soluble 
salts. 
ARTESIAN WATERS IDENTICAL WITH THOSE OF STREAMS 
The deeper waters of this section are of the very finest quality. 
The artesian and spring-waters that I have examined carry from 5 to 
16 grains of total solids to the imperial gallon, from 20 to 50 percent 
of which is silicic acid. The principal salt in these waters is sodic car¬ 
bonate. This is essentially the composition of the waters of the moun¬ 
tain streams, almost without any change. This is what we would ex¬ 
pect, provided our theory of artesian waters is correct. I have stated 
that the sands through which these artesian waters must flow are min- 
eralogically identical with the rocks of the mountains. These artesian 
waters are not so far below the surface as to absolutely preclude their 
having an influence upon the character of the alkalis, as they actually 
came to the surface, in the form of permanent springs. One, of which 
I have knowledge, has a flow of 20 second feet. Flowing wells are 
