PAPERS OX BOTANY 231 



eeptible steps to the Skokie Marsh, ^'est of the region. 

 The eastern line of the upland is the Glenwood bluff, 

 starting at the lake south of Xorth Avenue, Winnetka 

 and swinging west and south to the C. & X. TT. Ey. which 

 crosses it at about Willow Street. South of this it is 

 followed by the Gross Point Road which continues along 

 the bar bmit out from the end of the ridge. 



From this ridge the land slopes east more and more 

 gradually to the lake where it ends lq a steep bluff about 

 thirty to forty feet high. There is also a slight descent 

 toward the south. The second ridge, starting at the "Wil- 

 mette harbor follows a line a little west of south. It 

 rises ten to twenty feet above the land on either side, 

 which drops away with a gentle slope. A short spur ex- 

 tends northwest from this ridge .just north of Maple 

 Avenue, TVilmette. East of the ridge the slope is again 

 to the south and east for the northern portion where the 

 Calumet and ToUeston ridges approach each other is 

 higher. The slope is greater on the west side of the Calu- 

 met ridge for here the old TVilmette Bay was protected 

 by the bar. 



The ToUeston ridge rises only about five or ten feet 

 above and is not clearly defined north of Simpson Street 

 as the eastern side has been eroded by the lake. A nar- 

 row strip of sand and gravel forms the beach below the 

 wave-out bluff' which increases from about fifteen feet at 

 this point in Evanston to over sixty feet in Winnetka 

 where the upland appears. 



The whole region is underlain by the imworked glacial 

 till covered along the ridges and in local areas by deposits 

 of more or less stratified sand and gravel. The crests 

 and slopes of the ridges are well drained, but drainage 

 in the clay lowlands is veiy poor and wherever minor de- 

 pressions occur, water stands for a long time in the 

 spring. An attempt has been made to remedy this con- 

 dition by the digging of various small drainage ditches 

 and of the North Shore Channel, but numerous small 

 swampy areas still exist. 



Some idea of conditions in this region before it was 

 artificially drained is given by Frances Willard (14), 



