196 Kansas Academy of Science. 



SKETCH OF THE HISTORY. 



The history may be briefly summed up as follows : 



In the late Tertiary the Kansas river followed a course 

 approximating that shown in map 2. Its volume and gradient 

 m.ay have been less than now. 



Following that was the initiation of the continental ice 

 sheet, with a probable gradual elevation of the western Great 

 Plains. In the long interval in which the ice was accumu- 

 lating in the north and advancing enough to affect this region 

 directly, there may have been an increase of precipitation 

 here which would have quickened stream erosion. 



In time the ice began to creep over the northeastern divide. 

 The Big Blue and the Kansas below their junction had their 

 volume materially increased. Later Rock and Camp creeks 

 were also swollen, and together they deepened and broadened 

 the channels in map 3. 



This stage was finally ended by the damming of the river 

 by the ice and the filling of Kaw Lake as shown in map 4. The 

 lake may have lasted a few hundred years. 



The streams already mentioned, with increased vigor, built 

 up deltas in the lake, while streams directly from the ice 

 contributed perhaps even more. Small icebergs from the 

 glacier, helped somewhat by river ice, scattered bowlders over 

 most of the lake. Their numbers would be inversely as the 

 distance from the edge of the ice sheet. 



The bowlders lining the outlet may have come, a very few 

 of them, from the lake, but most of them from the edge of 

 the ice close along its northeastern side. 



When, by the retirement of the ice, the lake disappeared, 

 the river found its former channel much the same as before, 

 and itself for a time much larger. 



As the ice receded and dwindled the streams diminished to 

 their present proportions and gradually cut do\\Ti to their 

 present level. 



The terrace may mark a flooded stage corresponding to the 

 close of the Wisconsin stage of the ice age. 



University of Kansas, Lawrence. 



