Kansas During the Ice Age. 35 



of Manhattan at about 1,175 feet. From Manhattan to Wa- 

 baunsee it follows a very irregular line at the last-mentioned 

 level. One of the irregularities is that an old channel run- 

 nmg west of Manhattan, past the Kansas Agricultural College, 

 carries bowlders several miles to the southwest (and some h?ve 

 been reported as far away as Fort Riley). From a little east 

 of Wabaunsee the limit runs southwest to Mill creek, near 

 McFarland ; then along that stream to Maplehill ; thence south- 

 east past Dover to the Wakarusa at Auburn ; thence along that 

 stream, with declining altitude (except south of Clinton, where 

 it rises to nearly 1,200 feet), it leaves the state near Kansas 

 City at an altitude less than 1,000 feet. This limit includes the 

 drift scattered by channels, and probably lakes, leaving con- 

 siderable surface within it which is driftless. At the maxi- 

 mum of the ice sheet the drainage of the whole western edge 

 of the great ice sheet from Canada southward must have passed 

 around the ice within this margin, hence, much of the marginal 

 drift was stream-laid and probably some of it scattered in 

 lakes. 



The Limits of Till. The horizontal extent of the till cannot 

 be very definitely determined. Though it may reach a thick- 

 ness of fifty feet or more in places in the northeastern counties, 

 further south and west it becomes very thin and patchy. It 

 was evidently left so by the ice, but erosion has made it still 

 more attenuated. Only scattered bowlders can now be found, 

 where till patches may have once been a few feet in thickness. 



With this qualification, the limit of typical till can be given 

 as follows : A few miles east of Marysville, a little east of 

 Irving, a mile west of Fostoria, three or four miles west of 

 Wamego, four or five miles north of Paxico, four miles north- 

 east of Topeka, about ten miles north of Lawrence, a little 

 north of Lenape, and north and east of Kansas City, Kan. 



The vertical range of till reaches 600 or 700 feet, the high- 

 est point being near Blaine at about 1,500 feet, and the lowest 

 at Kansas City at less than 800. In the four or five north- 

 eastern counties of Kansas exposures of redrock near the up- 

 land level are rare, because the till covers all, but watercourses 

 which have cut down 50 or 75 feet below usually show numer- 

 ous exposures of older rocks with till resting on them. In the 

 deep valleys of the creeks till is usually restricted to the 

 higher levels, from 150 to 200 feet above the bottom of the 



