QUATERNARY AGE. 295 



of them have been overflowed ^nce the settlement of the country. 

 The one element of uncertainty about them is, when located near 

 the river, the clanger of being gradually washed away by the un- 

 dermining action of the water. Sometimes during flood-time, when 

 the current sweeps the bank, it is so insiduously undermined that,, 

 for several rods in length and many feet in breadth, it tumbles into 

 the river. This cutting of the river is greatest when it com- 

 mences to fall. Where the bank is removed on one side it gener- 

 ally is built up on the other. The old town of Omadi, in Dakota 

 County, is an instance of this kind. So rapidly did the river cut 

 into the bank, that many of the houses could not be removed, and 

 fell victims to the flood. The river cut far enough to the west of 

 the old site to leave it and its own bed, after being blown full of 

 sand, to be grown up into a forest of cottonwood. 



When now we bring into our estimate all the river bottoms of 

 Nebraska, and the tributaries of these rivers, and reflect that all 

 these valleys were formed in the same way, within comparatively 

 modern geological times, the forces which water-agencies brought 

 into play almost appal the mind bv their very immensity. So well 

 are these bottom-lands distributed that the emigrants can, in most 

 of the counties of the State, choose between them and the uplands 

 for their future home. In some of the new counties, like Fillmore, 

 where bottom-lands are for apart, there are many small, modern 

 dried-up lake beds, whose soil is closely allied to that of the valleys 

 Not unfrequently is the choice made of portions of each, on the 

 supposition that the bottom-lands are best adapted for the growth 

 of large crops of grasses. But all the years of experience in culti- 

 vating uplands and bottoms in Nebraska leave the question of the 

 superiority of the one over the other undecided. Both have their 

 advocates. The seasons as well as the location have much to do 

 with the question. Some bottom-lands are high and dry, while 

 others are lower and contain so much alumina that in wet seasons 

 they are difficult to work. On such lands, too, a wet spring inter- 

 feres somewhat with early planting and sowing. All the uplands, 

 too, which have a Loess origin, seem to produce cultivated grass as 

 luxuriantly as the richest bottoms, especially where there is deep 

 cultivation on old breaking. Again, most of the bottom-lands are 

 so mingled with Loess materials, and their drainage is so good that 

 the cereal grains and fruits are as productive on them as on the 

 high lands. The bottom-lands are, however, the richest in organic 



