Feb. 16,1914 
Indicator Significance of Vegetation 
373 
absence of carbonates, the higher sodium, and the lower magnesium are the most 
definite variations from the oceanic standard; but the general similarity, the identity 
of type, is unmistakable. * * * 
All the waters tributary to Great Salt Lake, so far as they have been examined, 
contain notable quantities of carbonates, which are absent from the lake itself. These 
salts have evidently been precipitated from solution, and evidence of this process 
is found in beds of oolitic sand, composed mainly of calcium carbonate, which exist 
at various points along the lake shore. The strong brine of the lake seems to be inca¬ 
pable of holding calcium carbonate in solution. 
The analyses as given in Table II report the presence of carbonates 
in solution in the lake water in only one instance. 1 It is in this respect 
that the saline matter of the soils more distant from the lake differs most 
markedly from the type just considered. Calcium carbonate was 
found widely distributed in the soils of the valley. Sodium carbonate 
was often found also, usually in small amounts (0,05 to 0.10 per cent 
of the dry weight of the soil), but occasionally samples were collected 
containing as high as 0.25 per cent. Sodium carbonate was found most 
frequently in the samples collected in areas where Kochia was growing. 
These soils were also highly calcareous. The available data on the dis¬ 
tribution of sodium carbonate do not, however, indicate that it can be 
correlated with the presence of any particular plant community. 
The composition of the salts of Great Salt Lake would lead one to 
expect that the chlorids would prove to be the most common and widely 
distributed of the saline constituents of the Tooele Valley soils, and such 
has been found to be the case. In the course of the work a quantita¬ 
tive examination for chlorids was made of 162 samples of soil, and all but 
13 samples showed the presence of measurable quantities of chlorids. 
Of these 13 exceptions 12 were samples from Artemisia tridentata (sage¬ 
brush) areas which are characterized by a very low total salt content. 
The sodium-chlorid content of the areas examined, all of which were 
occupied by vegetation of one type or another, ranged from a trace in 
the land occupied by Artemisia to over 2 per cent in land occupied 
by Allenrolfea occidentalis. Outside of the sagebrush areas the sodium- 
chlorid content of most of the samples fell between 0.4 and 1.3 per cent. 
In a large majority of the samples examined sodium chlorid constituted 
more than one-half of the total water-soluble material. 
Sulphates are usually present in the soils containing an excess of salts. 
Of 122 samples examined 96 showed the presence of sulphates. It is 
well recognized through the researches of Hilgard and others that cal¬ 
cium sulphate is a corrective for the soluble “black alkali” (sodium car¬ 
bonate) , the reaction between these salts resulting in the formation of the 
1 F. K. Cameron has shown, however, that while the lake water at its normal concentration does not 
give an alkaline reaction with phenolphthalein, this reaction will develop simply by diluting the lake 
water with distilled water. At the normal concentration of the lake, the dissociation of the sodium car¬ 
bonate is held back through the great number of sodium ions resulting from the dissociation of the sodium 
chlorid. The lake does, therefore, carry a slight amount of sodium carbonate. (Gardner, F. D., and 
Stewart, John. A soil survey in Salt Take Valley, Utah. U. S. Dept. Agr., Div. Soils Field Operations, 
Rpt. 64,1899, p. 104-105. 1900.) 
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