Soils of Nebraska — Hicks. 43 
of the old Tertiary lake, aud it owes its fertility directly to the 
sediments deposited there. Much of that sediment is indistin- 
guishable from the loess of eastern Nebraska, one of the best 
foundations in the world for a fertile soil, as shown more fully 
below. Both are freshwater formations, much resembling the 
•dried mud of existing lakes and rivers, whose fertilizing qualities 
are exemplified in bottom lands, in the beds of lakes reclaimed 
by drainage and in the effects of the overflowing waters of the 
Nile upon the lands of Egypt. 
This completes the enumeration of the bed rocks of Nebraska, 
as they are delineated upon the accompanying may . There are 
two additional formations not represented on the map, but men- 
tioned in this paper because of their great and direct influence 
upon the soil. These are the glacial drift and the loess, both of 
which belong to the Pleistocene or latest period of geological 
history. They are not shown upon the map, for two reasons. 
In the first place, their extent in Nebraska, especially that of the 
loess, is not thoroughly known. In the second place, they over- 
spread several of the older formations so completely that if 
they were represented on the map the underlying formations 
would be hidden. It would require a separate map to exhibit 
these Pleistocene deposits, or two maps in addition, since the 
loess partially overlies the drift, and requires a map by itself. 
The glacial drift is composed of sand, gravel and clay. It was 
carried down from the north or north-east, and spread over the 
eastern part of Nebraska by the agency of ice, or of ice and 
water combined. The clay of this drift sometimes forms a 
''gumbo" soil as, indeed, the clay of any geological age may 
do, if not mixed with sand and lime. 
But in general the glacial drift has about the right propor- 
tions of sand, gravel, clay, and lime (from the limestone peb- 
bles and bowlders) to form an excellent soil and subsoil. A 
soil formed from and resting upon glacial drift is usually loamy, 
■easy to till, with good drainage, and not soon injured by 
drought. The loess has nearly the same general distribution 
■as the glacial drift — /. e., it may be found over much the same 
territory, though neither drift nor loess covers every square 
mile of the general region in which they are found, and one 
may be wanting where the other is present. Whenever in 
Nebraska at least, both are present the loess is al)Ove the drift, 
