GEOLOGY AND PALEONTOLOGY. 159 
As has been remarked, the Dakota is the most important water-bearing bed of 
the plains, both on account of the quality and quantity of the water. Whatever 
theory we may adopt to account for the origin of the water, its presence, abun- 
dance, and purity are axiomatic. The amount of well-water that is utilized from 
the Dakota is probably greater than that of the spring-water. Wells begun in 
this formation usually find water in abundance at a depth of from ten to forty 
feet. In the overlying strata the depth to water depends on the thickness of these 
deposits, the flow being encountered at the line of unconformity, or, if the Da- 
kota, at that particular spot, consist of sandstone, at a short distance below that 
line. The probability of water being found in the Dakota is so great that, in 
order to estimate the depth of a well in any locality underlaid by this group, it 
is only necessary to know the thickness of the overlying deposits. Advantage is 
taken of this fact in preparing water maps of the various regions. One of the 
best of these is by N. H. Darton,** in which the ‘‘depths to Dakota sandstone, 
which usually yields abundant water-supplies’’ is graphically represented in 
colors. Such a map might well be prepared of the entire line of Dakota out- 
crops and would be of extreme economic as well as scientific value. 
As in the case of springs, the wells of the Dakota may be divided into fresh- 
and salt-water wells. The former so universally predominate, however, as to be 
understood, unless the others are specifically mentioned. Salt-wells in the 
Dakota are ordinarily found only in the vicinity of salt-springs and marshes, 
particularly near Lincoln, Neb., and in north-central Kansas. The water in few 
of these wells is sufficiently saline to prevent its use, although in a few cases this 
phenomenon has been recorded. The water-supply of but one of the several 
artesian basins in Nebraska can with certainty be referred to the Dakota. This 
is the northeastern basin, in Knox, Cedar and Dixon counties. This region is in 
reality a continuation of the James and Missouri river artesian basin of South 
Dakota. The wells in this part of the state find artesian water at a depth of 
from 300 to 600 feet. The deep artesian wells at Lincoln and Beatrice pass 
through the Dakota and find their supply in the Carboniferous, at a depth of 
from 300 to 2000 feet. 
One rather interesting fact connected with Dakota wells should, perhaps, be 
noticed here. It often happens that a farmer whose buildings chance to be situ- 
ated in a Permian valley near a Dakota hill fails to obtain a sufficient supply of 
water by digging. Orit may be that the water which he finds is so strongly 
impregnated with gypsum or other salts which permeate the upper beds of the 
Permian that it is not fit for use. Not infrequently, after having sunk several 
wells in the vain hope of obtaining a sufficient amount of good water in the 
valley, in despair he puts down a well on the top of the hill, in the Dakota sand- 
stone. In such a case he often surprises himself and his neighbors by obtain- 
ing an abundant supply of the best of water. Instances of this kind are often 
pointed out to the itinerant geologist as freaks of nature. The reasons for the 
phenomenon are obvious. 
ECONOMIC VALUE OF WATER. 
The region of Dakota outcrops is distinctively a grazing country. Except in 
the valleys of the larger streams, or on the uplands where the sandstone is coy- 
ered by later deposits, the greater part of the area is devoted to cattle raising. 
The sandstone hills produce the most nutritious grasses in the greatest profu- 
sion. Thousands of cattle are annually shipped to these ranges from the west, 
fattened during the summer, and in the fall sent to eastern markets. Some of 
56. Water Sup. and Irriga. Papers, U.S. Geol. Surv., No. 12, pl. xvi. 
