HLAWoRrTH. | Physiography of Western Kansas. 37 
over the flood plains of the Smoky one can dig in the river sand 
only a few feet, rarely over 20, until the solid Cretaceous floor is 
reached. The river channel itself in many places exposes the Cre- 
taceous. These conditions show that the river has scarcely yet 
reached its base level. Probably in a considerable part of its course 
it is still deepening its channel. From the vicinity of Salina east- 
ward, the condition of base level has doubtless been reached for 
some time. The unusually wide valley at Salina and the relatively 
wide valley from Salina eastward imply a much longer period for 
widening the channel than has existed farther to the west. 
The particular direction of the river in places is of great interest. 
Nothing of special importance is noticed in this connection above 
Ellsworth. But from Ellsworth to Salina the course of the stream 
is quite remarkabie. At Kanopolis a great ox-bow form reaches 
to the south a distance of three miles, while just east of Kanopolis 
a similar ox-bow carries the river to the north. Such ox-bow forms 
are repeated to the eastern side of Ellsworth county. As best one 
can judge from examining them on the map these forms are in 
every way similar to the ox-bow forms produced by a stream 
meandering across its flood plain after it has reached base level. 
The cause of such forms has not yet been determined. Possibly 
they are due to the shape having been assumed in earlier times when 
the elevation of the western part of the great plains area was so 
limited that the stream had a sluggish movement and meandered 
as though it had reached base level. Possibly it is due to the 
peculiar variation of the hardness of the formations through which 
the channel is cut, and its consequent variable ability to resist decay. 
From the eastern line of Ellsworth county the river bears still 
further to the south until a point near Lindsborg is reached where, 
with a bold curve, it passes to the northeast and north by way of 
Salina. Krom the Ellsworth county line eastward the valley grad- 
ually becomes wider. At Marquette it is about two miles wide, at 
Lindsborg it is nearly four miles wide, at Bridgeport it is approxi- 
mately six miles wide, while still further down in the vicinity of 
Mentor and Salina it is eight or nine miles wide. The peculiarity 
of direction from Kanopolis to Lindsborg may possibly be due to 
the extraordinary thickness and hardness of the Dakota sandstone 
