. ///>•(/// Pc/'osifs of ]Vyoraing. — Read 167 
frpm unknown depths below by osmotic action and the vohinic 
of strata from wliich the supply may be derived might thus be 
immensely increased. That the latter is the more probable 
source would seem to be indicated by the fact that shallow 
wells sunk near some of the dc]iosits have yielded water that 
is fairly palatable, and also the results of the work of the Ex- 
periment Station upon hydrography in the area go to show that 
seepage from precipitated moisture is very small in amount. 
We now^ see how the amount of w-atcr supplied and the strength 
of solution arc counterbalancing, for the amount of salts 
brought to the surface yearly is constant and all would be car- 
ried into the basin, irrespective of whether the precipitation 
was great or small. 
In the latter case the computation should rather be based 
on the area of the drainage basin, the average yearly evapor- 
ation from the soil, and the strength of the subsurface solu- 
tions. So many unknown quantities are here involved that 
such a computation is impossible wath our present knowledge, 
so that we shall have to allow the original computation to 
stand, with due allowance for its errors of assumption. 
In regard to the theory of the origin of these deposits from 
springs, certain conditions are obvious. The water must carry 
only small amounts of salts, or else much larger deposits must 
have- been formed. Springs highly charged w'ith salts, even 
though they did not break out into nndrained depressions 
which m.ight serve as evaporating basins, would necessarily 
have produced small deposits. We have no instances of de- 
posits except in these depressions, and it is of course absurd 
to assume that such springs would break out in such depres- 
sions alone. We have no record of any spring in the state 
which carries more than 150 grains to the gallon of the salts 
we, have been considering. 
In the second place, the flow of such springs must be small, 
or else w-e would not have the drying up of the deposits in 
the summer months, which is so characteristic of the greater 
number of them. There are numerous cases where alkaline 
lakes do not dry up during the summer months, but in no case 
is the alkalinity of the waters of these sufficient to justifv the 
assumption of contnuous evaporation of an alkaline supply. 
