110 Kansas Academy of Science. 



This would imply a stream 275 to 300 feet higher than the pres- 

 ent James river, occupying at that time the valley of that stream, 

 which would seem an insurmountable objection to our conception. 

 There are three things which reduce the difficulty. First, by 

 noting that the Wisconsin ice-sheet may have removed 150 to 200 

 feet depth from the bottom of the valley. There seems to be some 

 evidence of this when we find bed-rock considerably over 100 feet 

 higher on the south of the Missouri at Yankton and Vermilion, 

 S. Dak., than on the north side of the same. Secondly, there may 

 have been more or less of lacustrine conditions between the Mis- 

 souri and Big Blue rivers in northeastern Nebraska. This agrees 

 with the lack of coarse stratified deposits in that region, so far as 

 is yet known. Yet the pebbly clay shows unusual stratified fea- 

 tures near Westpoint and west of Fremont. Thirdly, the more 

 recent elevation of central Kansas, or the depression of areas to- 

 ward the northeast, in Iowa and Wisconsin. 



At Blaine, Pottawatomie county, Kansas, nearly at the extreme 

 advance of the ice in that state, clear evidence is shown that locali- 

 ties over 1500 feet above sea-level were swept over by the ice-sheet. 

 This is nearly twice the altitude of central Iowa. How then could 

 the ice have taken such a westerly trend, with lower or equal plains 

 southeast, in southeastern Iowa and Illinois, unless there had been 

 an appreciably western or southwestern slope of the preglacial 

 surface ? Such a condition would have rendered the drainage line 

 suggested considerably more rational. As we have found it the 

 slope seems much too steep eastward down the Kansas and too flat 

 or sluggish from the Missouri to the Blue. 



A speculation easily following from this conception is that not 

 long before the glacial advent, possibly the difference in slope of 

 the surface may have been enough to have reversed the flow in the 

 valley of the Kansas and it may have flowed via Salina and 

 McPherson through the buried channel at the latter place into the 

 Arkansas river. The accumulation of the ice on the northeast may 

 have reduced the slope of the stream so that it aggraded rapidly, so 

 that the McPherson channel was filled, and when the great stream 

 draining the west edge of the ice-sheet arrived, the surface in time 

 was tilted so that the drainage was eastward around the edge of 

 the ice, as we have seen. 



PLEISTOCENE AND MORE RECENT EROSION. 



Doubtless to some a great objection to our view will be found in 

 the amount of erosion which it assumes. It really infers that the 

 main valley of the Kansas river was three to four miles wide and 



