HAwortH. | Physiography of Western Kansas. Wy 
have a correspondingly high velocity. Scarcely a creek can be 
found in this part of the state as much as five miles long, which 
rises in the main uplands of the Tertiary plains, that has not pro- 
duced a channel from a quarter to a half mile in width in the lower 
part of its course, with the greater part of the channel floor 
entirely covered by these residual sands, sometimes to a depth of 
10 or 20 feet. The evidence regarding the origin of the sands in such 
a case is so apparent that little doubt can be entertained regarding 
it. On the higher uplands away from the drainage channels sand 
dune areas often are found miles in extent, the accumulation of the 
sands of which probably being of this same nature. Likewise gravel 
beds are frequently produced in the valleys of the arroyos and larger 
streams—beds composed of the residual materials left behind after 
the clays and finer sands have been carried away by the water of the 
streams. In many such cases it is easily seen that the gravels have 
been moved but a short distance from their previous home in the 
Tertiary formations. 
Streams cutting their channels into the Niobrara and Benton 
limestones and shales leave but little residual materials in their 
course. The character of the limestones and shales is such that the 
erosive processes consume almost everything that is worn loose. 
Occasionally limestone boulders of various sizes are produced which 
are left behind along the valleys of the streams, but they are by no 
means common. 
Eastward in the Dakota areas we have a condition similar to 
that in the Tertiary. The weathering action of the atmosphere 
and the abrasive action of running water have produced a large 
amount of loose Dakota sands, which are blown here and there 
over the valleys and flood plains of the different streams. In places 
on the high uplands where it appears the Dakota sandstone pre- 
viously existed, it seems that it is largely crumbled to a loose sand 
which is scattered over the general surface, and blown by the 
winds into sand dunes and sandhills similar to those in the far west. 
Methods of Erosion. 
Some of the present peculiar features of the erosive channels in 
the western part of the state are undoubtedly quite recent in origin. 
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