ILLINOIS RIVER DRAINAGE BASIN 521 



mckee's creek. 



This western tributary of the Illinois enters about 18 miles below the 

 mouth of Crooked Creek, and has an estimated drainage area of 472 square 

 miles. Its general course is southeastward from eastern Adams, County, 

 across southern Brown and northeastern Pike counties. Within a mile of its 

 mouth it is joined by South McKee's Creek, which drains the northeast 

 part of Pike County. 



The greater part of the divide between McKee's Creek watershed and 

 the small streams leading directly west into the Mississippi follows a series 

 of ridges which belong to the system formed at the margin of the Illinoian 

 drift sheet. Not only have these ridges been influential in determining the 

 position of this divide, but, as already indicated, they have governed to 

 some extent the courses of the small streams directly tributary to the 

 Mississippi. The divide between Crooked Creek and McKee's Creek is 

 nearly free from drift ridges, and stands but little higher than the borders 

 of McKee's Creek Valley. Its elevation is, however, perceptibly greater 

 than that of the immediate borders of Crooked Creek. The thickness of 

 the drift is generally sufficient throughout this watershed to fill the pre- 

 glacial drainage lines and render it necessary to develop lines along new 

 courses. 



INDIAN, MAUVAISE TERRE, AND BIG SANDY CREEKS. 



Indian Creek is one of several small eastern tributaries of the Illinois 

 entering the portion of the valley south of the mouth of the Sangamon. 

 It has a drainage area of about 290 square miles, situated mainly in north- 

 em Morgan County. Its lower 10 miles are occupied in crossing the Illinois 

 River bottoms, where it has little drainage outside its immediate channel. 

 Its watershed on the uplands has a breadth of about 9 miles and a length of 

 fully 20 miles. The general course of drainage is directly westward, across 

 a gently sloping plain, and is independent of preglacial drainage lines. 

 The divide at the east, however, is probably a preglacial rock divide. 



■ Mauvaise Terre Creek drains a narrow strip immediately south of the 

 Indian Creek watershed and has a drainage area of 275 square miles. It 

 includes a strip leading westward across central Morgan County and north- 

 ern Scott County, whose average width is scarcely more than 8 miles, but 

 whose length is about 30 miles. Like Indian Creek, its course seems to 



