POTASH SALTS AND OTHEK SALINES IN THE GREAT BASIN EEGION. 29 
solved solids will be correspondingly low. This is true in California waters, the 
average silica for the humid-region rivers being 13.4 per cent and for the semiarid- 
region waters 8 per cent of the total mineral matter in solution. The principal effect, 
then, of climatic condition on silica content is a negative one and it is apparently 
due merely to change in total mineral content. 
!* "By the decay of the abundant organic material in humid regions carbonic acid 
is set free, being dissolved in the surface waters or entering the air as carbonic dioxide. 
This carbonic acid, uniting with the carbonic acid of the alkaline-earth carbonates, 
produces the bicarbonates which are readily dissolved, so that surface waters in 
regions of abundant rainfall carry large amounts of the bicarbonate radical and of the 
alkaline earths. In regions of deficient rainfall, on the other hand, carbonic rocks are 
attacked to less extent and the gypsum and alkaline sulphates that are present are 
brought more largely into solution." 
The conclusions of Van Winkle and Eaton may be applied to basin conditions. 
A somewhat different grouping of the basin rivers is desirable, and I have attempted 
this in the following. This grouping is not accurate, for the reason that some of the 
basin streams rise in the higher mountains and under conditions similar to many 
of the streams upon the western slope of the Sierras, while the lower courses of these 
streams are in the valleys and under semiarid or arid conditions. Three groups are 
made: 
(1) Streams which have watersheds under humid conditions. These are Mill Creek, 
Leevining Creek, Rush Creek, the mountain streams tributary to Owens River, 
and the short streams of the higher ranges of the basin. 
(2) Streams which have watersheds partly under humid conditions and partly under 
arid. These are the Truckee, Carson, Walker, streams tributary to Great Salt Lake, 
and streams tributary to the southern Oregon lakes. 
(3) Streams which have watersheds under arid conditions. These are the Quinn, 
Armagosa, Humboldt, Reese, and Owens Rivers. 
Streams of the first group are comparable to such rivers as the Yuba and the Tuo- 
lumne, and the California streams for humid conditions generally. Streams of the 
second group are comparable with the California streams under semiarid conditions. 
Streams of the third group are in a class by themselves, and, in the absence of detailed 
studies, can not be properly characterized. 
The streams tributary to Great Salt Lake are characterized by high chlorine content, 
while the streams of the Lahontan Basin have a high sulphate content. Owens River 
is the only stream in which a noticeable amount of nitrates has been reported. 
Lake waters are similar in composition to the river waters. There are some differ- 
ences, and in order to show this I have worked out certain ratios which are given in 
the accompanying table. 
Ratios between certain soluble constituents in lake and river waters. 
Source of sample. 
Na 
K 
Ca 
Mg 
CI 
SO< 
H COs+COj 
CI+SO4 
Rivers: 
Ogden 
2.7 
2.0 
2.6 
2.8 
2.1 
8.1 
3.9 
4.12 
1.50 
3.97 
1.13 
.15 
.52 
1.11 
.58 
.56 
.61 
9.29 
12.73 
7.81 
9.73 
1.11 
1.81 
2.50 
3.50 
18.9 
4.8 
1.16 
Weber 
1.74 
Bear 
.53 
Jordan 
Humboldt 
4.6 
11.9 
2.45 
Amargosa 
.30 
Walker 
6.0 
3.2 
/ 3.5 
\ 2.6 
.14 
1.10 
.10 
.70 
.56 
.40 
2.00 
1.28 
Truckee 
2.2 
1.63 
Owens 
2.35 
Lakes: 
Great Salt 
6.6 
18.9 
16.0 
4.5 
2.42 
Winnemucca 
.15 
Pyramid 
.30 
Humboldt 
.61 
Walker 
.38 
Mono 
20.4 
23.6 
18.6 
27.1 
.64 
Owens 
.70 
Harney 
.73 
Abert 
.54 
Sevier 
.04 
CALIFORNIA RIVERS. 
Mean of rivers in semiarid region . 
Mean of rivers in humid region. . . 
0.83 
2.64 
