History of Kaw Lake. 195 



this state, but from Nebraska, and possibly from Dakota, for 

 at that time we may suppose that the surplus drainage of all 

 the western edge of the ice sheet and of the eastern slope of the 

 Rockies may have come through the Big Blue. We can believe 

 that it built up quite a delta where it entered the lake, which 

 has since been mainly removed. The filling of the channel 

 north of Manhattan may be considered a portion of it which 

 has been preserved by its position. 



The lacustrine deposits are coarser below, even carrying 

 pebbles and a few bowlders near the bottom, but fine silt 

 resembling loess above. The sand is thicker toward the east, 

 and some of it whipped out of stream channels covers much of 

 the surface, including the highest points northeast of St. 

 George. Further west the surface is more clayey. 



6. The Reopening of the Kansas Channel. 



Little need be said of this. The melting of the ice, as the 

 Kansan glacier finally withdrew, probably left the channel 

 much as it was when the ice came. The ice did not last long 

 enough, probably, to bring much till into it. Thus far, at 

 least, none has been discovered, though it is not improbable 

 that some may be found in time. It is probable that when the 

 Kansas first retraced its old course that it lowered the level of 

 Kaw Lake quite rapidly; that the stream was rapid and vig- 

 orous and loaded with coarse material from the adjacent ice 

 sheet. As the amount of water declined there was a stage of 

 rapid aggradation which filled the valley lower down. The 

 thick river deposits in the terrace northwest of Lawrence, 

 back of Cameron's bluff, may be referred to this stage. 



7. The Formation of the Lower River Terrace. 



Reference has been made to a silt-capped terrace west and 

 north of Wamego. It doubtless was formed since the drain- 

 ing of the lake and marks a stage in the history of the river 

 since its reopening. Wells show that the bedrock underneath 

 is not as deep as under the present fiood plain. Trace of the 

 same terrace may be seen south of the river below Antelope 

 creek, and above and below Wells creek. Without doubt, study 

 will find out other fragments of it, and it may possibly be 

 correlated with the terrace at Kansas City, which is there 

 over 100 feet above the river. Here it is only 40 to 60 feet 

 higher. 



