38 
Colorado Experiment Station 
also struck at depths so shallow as 65 to 75 feet. The character of these 
waters, even if they carried many times as much matter in solution as 
they do, preclude them as the primary source of such alkalis as we 
have been describing. 
Without any change in the geological formation or surrounding 
conditions, we pass to an area in which the alkali relations are entirely 
different, and here we find a coincidence in the character of the salts 
in the water contained in the strata, the salts in the soil, and the alkalis, 
which, on the surface, are becoming more and more serious, in that 
they seem to be changing in their character, i.e., becoming richer in 
carbonates. 
The waters of the artesian wells probably present these facts more 
plainly and simply than do the alkalis themselves though the differences 
show very plainly in these. It is useless in this connection to multiply 
examples, so I will choose only two waters, and some alkalis. The two 
waters that I shall give are about 6 miles apart, located on a north and 
south line. There is less than 20 feet difference in level between the two 
places and they are in the same geological formation, while the whole 
area is surrounded by high mountains of metamorphic and igneous 
rocks. 
The well at the southern end of this line yields a flow of 1 cubic 
foot per second of good water, carrying 15.9 grains of total solids in 
the imperial gallon, of which 50 percent is silicic acid and 34 percent 
is sodic carbonates. The well at the north end of the six-mile line car¬ 
ried 103.6 grains of total solids, of which only 3/10 of 1 percent was 
silicic acid and 89 percent was sodic carbonate. The former well is 
923 feet deep, while the latter was 500 feet deep, but it has 'been closed 
for a number of years. Deeper wells still further north of this point, 
are even richer in total solids and carbonates, though the increase is 
not great. There are only very small amounts of either sulfates or 
chlorids in either of these waters. To state the differences of these 
waters in other words, the one contains only a small amount of ma¬ 
terial in solution and the other contains seven times as much; the one 
contains relatively much silicic acid, the other very little. The total 
solids from the one at the southern end of the line contain 34 percent, 
those from the one at the northern end, 90 percent of sodic carbonate. 
There are only small quantities of sulfates and chlorids present in 
either water. 
I have said enough about the alkalis of the southern section; name¬ 
ly, that they are essentially sodic sulfate, containing quite frequently 
upwards of 90 percent of this salt and, excepting a few in which 
chlorids are very abundant, always consisting of sodic, calcic, and mag- 
nesic sulfates. The ground-waters are very similar. 
