36 
Colorado Experiment Station 
ehlorid. These represent the soluble portions of efflorescences as they 
were removed from the surface of the soil. 
The soil and subsoil were sampled at the point where the first 
alkali sample was taken and analyzed with the following results: 
ANALYSES OF SOILS 
NOS. 580 AND 
581 
No. 581 
No. 580 
Surface Soil 
Subsoil 
Percent 
Percent 
S?in d > .■. 
. 56.271 
51.285 
Silica . 
. 17.531 
11.662 
Sulfuric Acid . 
. 0.255 
0.128 
Chlorin . 
. 0.462 
0.184 
Carbonic Acid. 
. 3.956 
10.207 
Phosphoric Acid. 
. 0.651 
0.019 
Lime . 
. 6.900 
14.318 
Magnesia . 
. 1.619 
1.444 
Sodic oxid. 
. 1.464 
0.679 
Potassic oxid . 
. 1.047 
1.183 
Aluminic oxid. 
. 3.383 
2.868 
Ferric oxid . 
. 4.420 
3.567 
Manganic oxid (br) . 
. 0.192 
0.161 
Ignition . 
. 1.867 
3.085 
Sum . 
. 100.017 
100.790 
Oxygen equal to chlorin... 
. 0.104 
0.042 
Total . 
. 99.913 
100.748 
This was virgin soil and about 400 feet from a large drainage 
ditch. The ground-water at this time was 5 feet from the surface in a 
stratum of sand, beneath which was a yellow, marly clay. The pres¬ 
ence of marl in the subsoil was apparent by its color and manner of 
distribution. Its presence shows plainly in the analysis, being indicated 
by the 10.2 percent of carbonic acid against 3.9 for the soil, and 14.3 
percent of lime against 6.9) in the soil. 
The mineral constituents of this soil indicate the neighboring 
mountains as the source from which they came. The geological for¬ 
mation is designated as the Alamosa and consists of an alternation of 
sands and clays. The sands are very uniform in their mineralogical 
components, being those of the schists, granites, and igneous rocks 
which everywhere flank the valley. This alternation continues to a 
depth of more than 1,000 feet. I am informed that there is no change 
in this respect as far as any of the borings have penetrated, which I 
understand is 1,800 feet, of this figure I am, however, not certain. 
An analysis of the ground-water from this stratum of sand is 
added to complete the record of our examination of this particular 
place. The water carried 98.9 grains of total solids in the imperial 
gallon. Toss on ignition 16.9 grains. 
