158 KANSAS ACADEMY OF SCIENCE. 
creek, in southern Mitchell county, there is a large marsh that formerly contained 
3000 acres. In the same region are some springs of salt-water which issue from 
beds of sandstone, evidently the salt-marsh horizon, which outcrops fifteen feet 
or more above the level of the creek. Great Spirit spring, near Cawker City, 
owes its saline properties to the fact that its waters are derived from this horizon. 
The salt-marshes at Lincoln, Neb., are very similar to those in northern Kan- 
sas. They are located in the valley of Salt creek, near the western outskirts of 
the city of Lincoln. Several branches of Salt creek converge near by, forming a 
broad and nearly level bottom, containing several thousand acres. Over this bot- 
tom the salt flats or marshes are scattered for several miles up and down the 
creek. The small streams which converge near Lincoln all contain fresh water 
except one. Haines branch, which flows from the southwest, contains along its 
lower course hundreds of salt-springs, not dissimilar to those described from 
Mitchell county, Kansas, except that they issue from mud banks near the water, 
instead of from the sandstone at a higher level. This may be accounted for by 
the fact that in the vicinity of Lincoln post-Cretaceous erosion has removed the 
sandstone. 
In general appearance these marshes are so similar to those in Kansas that, 
on casual examination, no marked difference can be observed; both have the 
same flat surface, salty incrustations, and seepage springs near the margin and 
on the bottom. The strength of brine varies little, and in early days salt was 
obtained for commercial purposes from either locality. Both occupy the same 
general horizon, from 50 to 100 feet below the Benton, and the character of the 
rock from which the salt-springs take their rise is practically the same. Near 
Lincoln, as in Kansas, many of the wells in the Dakota yield salt-water. An ex- 
ample may be cited at the Yankee Hill brick-works, southwest of Lincoln. 
Doctor Hayden considered it probable that the salt-water of these marshes 
came from the Carboniferous shales, which in this vicinity are found at a depth 
of some 270 feet. The same author, however, considered that the Kansas 
marshes derived their supply from the same horizons. Later geologists are di- 
vided on the question, some contending for the Carboniferous, others for the 
Dakota age of the salt. One fact that gives much credence to the position of 
those who look to the Carboniferous for the source of supply is that the shales 
of this age immediately below the Dakota are highly saliferous and the water 
contained in them has a strong artesian flow. This fact, together with another 
condition which seems fairly well authenticated, viz.: that the entire thickness 
of the Dakota in the vicinity consists of porous sandstones, with scarcely a trace 
of clay or shale, has been sufficient to establish the theory of Carboniferous 
origin. Other investigators have pointed out the similarity of these marshes in 
general appearance and geological position to those less than 100 miles away, in 
which the salt comes from undoubted Dakota horizons, and have drawn the in- 
ference that the salt-marshes at Lincoln and in Kansas must be similarly ac- 
counted for. 
To the writer it appears probable that one who had studied the conditions in 
the vicinity of Lincoln alone would be most likely to assign the origin of the salt 
to the Carboniferous. On the other hand, the geologist who had previously ob- 
served the conditions in other parts of the Dakota area, particularly in northern 
Kansas, would not be wrong in considering the saliferous shales of the upper 
part of this group as the true source of the salt in the Lincoln salt-marshes. 
WELLS, 
It is natural to suppose that a formation containing so many springs as does 
the Dakota would also furnish good well-water. This is almost universally true. 
