DRAINAGE OF THE KANSAS ICE-SHEET. 



-, By J. E. Todd, University of Kansas, Lawrence. 



/^\UR subject has been so shortened for convenience that it is 

 ^^ too broad for the intended scope of our paper. We have not 

 time to consider the drainage of the whole ice-sheet of the Kansan 

 epoch in the United States, but only that of its western side, and 

 particularly that in the state of Kansas. It is scarcely necessary to 

 state that it was in the Kansan epoch of the ice age that the great 

 ice-sheet reached its maximum extent; that in the lowan, which 

 has not been satisfactorily traced in the Missouri valley, the ice did 

 not extend as far by 150 to 200 miles in this direction. 



PROBABLE MARGIN OF THE ICE AT THAT TIME. 



Some have conceived that the center from which the ice deployed 

 at that time was a point west of Hudson's Bay, called the Kewatin. 

 They have assumed that the ice which entered Kansas came down 

 the James and Missouri river valleys through Dakota and Nebraska. 

 Such a conclusion, however, seems forbidden ' by the following 

 facts : 



1. It would have been impossible for such a long, slender lobe 

 to have maintained itself for 500 miles, with one side exposed for 

 that distance to the heat and warm winds of the western plains. 

 Moreover, the height of the ice in Dakota, necessary to give head 

 sufficient for such a course, must have been attended with a much 

 greater western movement in that latitude than is indicated by any 

 trace yet discovered. 



2. Northeastern Kansas would have been more accessible to a 

 Canadian ice-sheet through the Des Moines valley rather than 

 through the Dakota. The distance is shorter, and preglacial sur- 

 faces rise 1500 to 1700 feet above sea in northeastern Nebraska. 

 Besides, no clear trace of Kansan drift has yet been found in Dakota. 



If it be objected that the divide between the Des Moines and 

 the Missouri is too high, particularly when southeastern Iowa is 

 so much lower, it may be replied that 200 to 350 feet of the divide 

 is glacial till, and that the older surface is not over 1000 feet alti- 

 tude, and in the northern part, where the more easily eroded Cre- 

 taceous rocks are found, cases are reported of preglacial surfaces 

 less than 800 feet above sea. Moreover, there are other reasons 

 for believing the east was relatively higher at that time. 



(10-?) 



