216 Kansas Academy of Science. 



streams of uncertain direction. Little time has been spent on 

 them. They may be of Cretaceous time, the work of a stream 

 flowing into the Cretaceous sea a little farther west; or, more 

 likely, they may have marked the eastward course of a Tertiary 

 stream, a pioneer of the present eastward drainage, flowing across 

 the divide before the Kansas had swung into its present course, 

 and long before it had excavated its present valley. 



SKETCH OF THE HISTORY OF WAKARUSA CREEK. 



Putting the foregoing conclusions into chronological order, we 

 may sum up as follows: 



Following or attending the elevation of the Rocky Mountains, at 

 the end of Cretaceous time, the great plains became dry land and 

 sloped more and more toward the east. As a result, rivers began 

 flowing in that direction, possibly, though not certainly, outlining 

 something like the present Missouri system. There is con^derable 

 evidence that at first they ended in playa lakes and that there was 

 much aggradation and building up of alluvial plains. Eventually 

 they made their way through to the line of the Missouri or its pred- 

 ecessor, and the chert gravels may have been formed about that 

 time, before valleys had been deepened to any great extent. 



During the Tertiary there was first deposition and building up 

 of the Great Plains, but later erosion lowered the principal valleys 

 till, at the beginning of the Pleistocene, or at least when the ice 

 sheet arrived, they were about 100 feet higher than at present. 

 This is attested by remnants of preglacial gravels near St. Marys 

 and Topeka, and other marks of its position near Manhattan and 

 St. George. 



It is probable, as already suggested, that two or three short 

 tributaries of the Kansas flowed northward across and along the 

 present course of the Wakarusa. The eastern one may have 

 headed west of Vinland and followed approximately the course of 

 the Wakarusa eastward. The second may have headed in Rock 

 creek valley, received waters from Camp creek and Deer creek from 

 the west, and flowed along the line of Coon and Oakley creeks to 

 the Kansas. This theory has not been tested in the field. The 

 drainage of the area west of the Topeka limestone may have also 

 gone northward independently, or it may have joined the stream 

 just sketched. 



DURING THE PRESENCE OF THE ICE SHEET. 



.The ice, gradually approaching from the north, doubtless 

 swelled the streams receiving its water, and increased their erosion 

 and the coarseness of their deposits. In fact, the gravels marking 



