300 GEOLOGY. 



yet lakelets are numerous over portions of this region, some of 

 of which are alkaline and others freshwater. The latter can easily 

 be distinguished from the former at sight by the thick vegetation 

 growing around their margins, of which the former have very little, 

 and sometimes not a trace. It is at least evident that these fresh- water 

 lakes have had some common origin. Their fauna would prove 

 it. The same species of fish and fresh-water mollusks are found in 

 most of the large ones, even where there is no perceptible present 

 outlet. 



Although opposed to the views of eminent scientists, I have no 

 ■doubt that many of these hills are capable of cultivation, and some 

 day will be cultivated. In fact already many of them, that ten 

 years ago were barren of vegetation, are now covered by a vig- 

 orous growth of grasses, and some that are favorably located are 

 successfully included among the cultivated fields of adjoining farms. 

 Notable examples of this can be seen south of Lowell. The trans- 

 formation has been caused by the increasing rainfall of the State. 

 Not all of them, indeed, will be utilized until the rich lands that 

 border them are improved. But when better lands become scarce 

 and costly, advances will gradually be made on the sand-hills. 

 Already it has been proved that they produce corn, sweet pota- 

 toes and other root crops equal at least to the New Jersey sands. 

 The rich marl beds in their vicinity will supply an inexhaustible 

 source of fertilizing them. 



Much has been done by geologists in exploring these sand-hills, 

 still much more remains to be accomplished before all the causes 

 that produced them are thoroughly understood. 



Alkali Lands. 



Every one in Nebraska will sooner or later hear of the so-called 

 alkali lands. They are not confined to any one geological forma- 

 tion, but are found sometimes on the Drift, Alluvium, or the Loess. 

 They increase in number from the eastern to the western portions 

 of the State. Yet one half of the counties of the State do not 

 have any such land-;, and often there are only a few in a township or 

 county. Where they have been closely examined they are found 

 to vary a great deal in chemical constituents. Generally, however, 

 the alkali is largely composed of soda compounds, with an occa- 

 sional excess of lime and magnesia or potash. The following an- 

 alyses of these soils show how variable they are. The first is taken 



