46 ANIMAL ENVIRONMENT 



southward around the head of Lake Michigan, nearly parallel with the 

 shore, then northward into Michigan, there turning somewhat more to 

 the east (Fig. 2). Beyond the edge of the ice, early lines of drainage were 

 established and temporary lakes came into existence. All of our south- 

 ward flowing rivers bore the sediment-laden waters from the melting ice. 

 The results of this may be seen in the gravel and sand outwash, valley 

 trains, etc., along the DuPage and other rivers, the more sandy portion 

 usually being farthest downstream. 



In Southwestern Michigan, these early lines of drainage were by 

 the St. Joseph and the Dowagiac valleys. In the latter a small lake is 

 believed to have existed (Fig. 2). These waters did not flow into the 

 south end of the lake, as at present, but united and flowed down the 

 present course of the Kankakee River. The Kankakee marsh area and 

 the region at the mouth of the Kankakee (Morris Basin) are believed 

 to have been occupied by a lake. These basins are surrounded by sand 

 areas which are probably the oldest in our area of study. Dunes are 

 said to be present to the south and east of "Lake Kankakee," a few being 

 present on the moraine in the extreme southeast corner of our map 

 (frontispiece). 



The next stage was marked by the retirement of the ice from the 

 position of the Valparaiso Moraine to the present basin of Lake Michigan. 

 The drainage of glacial waters down the Fox, DuPage, and Upper 

 DesPlaines rivers stopped (Fig. 3). The lakes to the south and east 

 probably began to disappear. Later, the St. Joseph and Dowagiac 

 changed their lower courses and flowed directly into Lake Michigan, 

 which found an outlet by way of the lower DesPlaines. 



Now begins the history treated in the first bulletin of the Geographic 

 Society (60), and Bulletin 7 of the Illinois Geological Survey and else- 

 where (6 1, 62, 63, 64). The predecessor of Lake Michigan stood at a level 

 55 to 60 feet above the present lake. The stage is known as the Glen- 

 wood stage of Lake Chicago. Cliffs were cut, beaches of sand and gravel 

 were deposited, and dunes were formed. These are our second oldest 

 sand and gravel areas. Their position is shown on the map (facing p. 52). 



The water then fell to a level of 35-40 feet above the present lake. 

 This is known as the Calumet stage (Fig. 4). Here again cliffs and 

 beaches of sand and gravel were formed, and constitute our third in 

 point of age. These beaches have not been indicated on the map 

 because their distribution within the state of Michigan has not been 

 studied by physiographers. In the vicinity of Waukegan they are very 

 close to the Glenwood beach. 



