106 



LIFE OF THE PLEISTOCENE 

 K. ALTITUDE OE OLD LAKE BEACHES 



Dr. Goldthwait has measured the altitude above sea level of the three 

 highest beaches at several widely separated localities, 70 and his data are of 

 interest in connection with the previous discussion. 



Evanston and Niles Center, HI 



Zion City, Illinois 



State Line, Illinois and Wisconsin 



Line between Racine and Kenosha counties 



Holland, Michigan 



Spring Lake and Eastmanville, Mich 



South end of Lake Michigan basin 



Glenwood 



636 

 643 

 634 

 637 

 638 

 633 

 636 



Calumet 



619 



621 



616 



621 



621 



613" 



619 



Toleston 



605 



605 

 602 

 604 



L. INTERGLACIAL LIFE OE THE CHICAGO AREA 



Well records from different parts of the region indicate that more than one 

 ice sheet passed over the Chicago Area. Other preglacial conditions are also 

 indicated in several places. A buried valley enters the lake near Lincoln 

 Park, and can be followed for several miles back from the lake, in a north- 

 westerly direction. The wells drilled along this valley penetrate rock at 115 

 to 125 feet below lake level. 72 Rock is found at varying depths showing that 

 the region had suffered marked erosion previous to the glacial period. Some 

 of the depths at which rock has been found, and the location of the wells, is 

 of interest and illustrates this variation. 



Wilmette 



140 



Turner Park 



80 



Bowmanville 



80 



Washington Heights 



71 



Jefferson Park 



68 



Morgan Park 



90, 163 



Irving Park 



79 



Riverdale 



45 



Norwood Park 



90 



Dalton 



35^M) 



Near County Infirmary 



71 to 101 



Harvey 



20-25 



Oak Park 



45, 65, 85. 



Glenwood 



30-35 



Near Cragin 



20 



2Yi miles north of Arlington 









Heights 



195 



sequently rose to the Calumet level after the low water stage. It is also possible that the 

 low water stage was inter-Glenwood, as is suggested by some of the results of Alden's studies 

 near Milwaukee. 



70 Journ. of Geol., XVI, p. 464, 1908. 



71 Very obscure, probable error of few feet (Goldthwait). 



72 Leverett, Illinois Glacial Lobe, pp. 583-590. 



