The: Wate:rs of the: Rio Grande: 29 
the reason that the artesian waters, to be presented in this connection, 
will offer another phase of this, if not an entirely new question. It is 
for this reason that I call attention to the production of sodic carbo¬ 
nate in the decomposition of the felspars and at the same time to show 
that it is also possible to lay too much stress on this fact, as the sodic 
carbonate may be changed wholly into other forms. Still, it is a fact 
that sodic carbonate is almost always present in soil extracts and nat¬ 
ural waters in larger or smaller quantities. The original source and 
general distiibution of sodic carbonate may be easily explained, but 
these are not the questions to be answered in the case in hand, and do 
not answer the specific question presenting itself. 
It is evident that neither the ground-waters nor solutions of these 
alkalis or soil extracts from either side of the river find their way into 
it, for if they did, they would both increase the amount of salts in the 
river-water and change their character. 
THE ARTESIAN WATERS 
Artesian water in the San Ruis Valley was discovered by acci¬ 
dent in 1887 and I am informed that there have been sunk, up to the 
present time, more than 5,500 such wells, ranging in depth from about 
70 to upwards of 1,800 feet. It is indifferent, in our inquiry, whether 
any of these wells are used for irrigating purposes or not. Very many 
of these wells are now flowing at the surface, and but few of them 
are cased to any considerable depth and may consequently be furnish¬ 
ing water to the general supply of the valley by leakage, though they 
may not be flowing at the surface. We are, therefore, interested in 
the character of these waters. 
There is a thoroughly justified classification of these artesian 
waters into white and brown, according to their color. The color, 
however, is probably due to an accident, the occurrence of humified 
matter in the strata of certain portions of the valley. It is possible 
that some of the white waters may contain the same mineral constitu¬ 
ents as the brown water and that in as large quantities. This is more 
than a possibility, for every sample taken shows that the former 
statement, i. e., that the dissolved salts are the same in kind, is true, 
but the brown waters are usually richer in total solids. Two wells, 
locally designated as the gas-well and the soda-well, yielded waters 
which were not highly colored, but were comparatively rich in total 
solids. The water from the gas-well carried 37.63 grains, and that 
from the soda-well 103 grains of total solids per imperial gallon. In 
the brown water the upper flows are not strongly colored and are not 
excessively rich in total solids whereas the deeper flows are darker 
colored and are richer in total solids. The deepest flows, however, do 
not necessarily furnish the darkest waters. 
