26 Kansas Academy of Science. 



Now, this valley is a good sample of the valley of the Kan- 

 sas river preceding the coming of the ice, as is recorded by 

 the deposits of chert and gravel near the bottom of the chan- 

 nel, and the streams of ice frequently deposited granite 

 boulders in Louis Lake, and silt some thirty feet in depth, so 

 that we have the relation of the boulders, silts and sand, show- 

 ing the marks of the old channel, and from the divide between 

 Kansas river and Mill creek just southwest of the edge of the 

 ice sheet, which is marked by granite boulders as large as hay- 

 stacks to the southwest of this edge of ice. 



These boulders were covered with a layer of silt fifteen or 

 twenty feet in thickness, so that we have every evidence of a 

 rapid stream when the boulders were deposited. There is no 

 evidence of any boulder having been on the south of Man- 

 hattan. There is a valley, which is now occupied by the rail- 

 road from McFarland to Alma, fifty or sixty feet lower than 

 the former valley. This valley shows no boulders except in 

 the southwestern portion, where we may see it is so related 

 that the boulders may have worked back into this tributary 

 side channel. The chert gravels mark a deposit of the pre- 

 glacial Kansas river, and show its course passing through here 

 north of Manhattan. There are no boulders south of Man- 

 hattan, but in Reservoir Hill, north, they are abundant. The 

 tracings of the preglacial river are found near St. Marys, 

 north of Topeka, and were distinctly traced along to the 

 northeast of Lawrence. Into this valley came the ice bed of 

 the Kansas streams, filling the valley from Wamego to Le- 

 compton, passing all the drainage around the edge of the ice 

 sheet and then into this lake. As the ice receded, the first 

 effect would be to swell the stream and carry its sediment 

 along this channel, and perhaps fill it up, and when the ice 

 receded the stream would revert to its original channel, and 

 perhaps largely drain the lake, whose bottom would be no 

 lower down than the level of the preglacial channel. As the 

 ice receded there may have been a cutting down of the chan- 

 nel to its original depth or deeper, as may be observed in the 

 deep deposits of sand north of St. George. Since the Glacial 

 Period the river bed here has been cut down 250 to 300 feet 

 below the preglacial channel, so that if there were any 

 boulders here they would all have been carried to the lower 

 depths of the Kaw. 



