liv FISHES OF ILLINOIS 



and drains an area of 1,350 square miles (Leverett). Its water- 

 shed lies immediately southwest of that of Spoon River. It 

 extends on the northwest nearly to the bluffs of the Mississippi, 

 there being one tributary in northern Hancock county, from 

 which the Mississippi bluff is distant less than five miles. No 

 important tributaries enter from the west, but several creeks 

 lead into it from the east which have lengths of 15 to 20 miles 

 or more. These eastern tributaries present a remarkable paral- 

 lelism, and take a nearly uniform direction about S. 65° W. 

 One of them, known as East Crooked creek, occupies a valley 

 which continues beyond this watershed in a direct course to the 

 Mississippi and is thought to have been formed by a subglacial 

 stream. Shallow channels may also have been opened b}^ the 

 same agency along the other eastern tributaries and have occa- 

 sioned their remarkably direct and parallel courses (Leverelt). 



The whole of the drainage basin lies in the Illinoisan drift 

 and is very similar in character to the basin of the Spoon River. 

 For a few miles near its mouth the course of Crooked creek has 

 been determined by a pregiacial drainage line, but elsewhere the 

 drainage appears to be nearly independent of pregiacial lines. 

 A portion of the divide between the Spoon River watershed 

 and the Crooked creek watershed follows a low till ridge. 



In the first 14 miles of its course Crooked creek falls 100 

 feet, but the fall gradually decreases until in the last 20 miles 

 it is only 10 feet. The bluffs of the river, especially in the lower 

 part, are high and abrupt, rising to a height of 100 feet from the 

 water's edge for a large part of the distance. In only a few 

 places are bottom-lands found. They are short and never 

 more than one half of a mile in width. Limestone outcrops 

 are found all along the banks of the river. 



APPLE CREEK 



Apple creek has a drainage area of about 435 square miles, 

 which includes southeastern Morgan county, northern Greene 

 county, and northwestern Macoupin county. It rises in Morgan 

 county and flows southwestward to its mouth. Its basin has a 

 length of about 40 miles, and the greatest width is about 15 

 miles. The river is about 53 miles long. 



The entire basin lies within the Illinoisan drift. The lower 

 course of the river seems to be along the line of a pregiacial valley, 

 but the headwater portion and also a majority of the tributaries 

 show little dependence upon pregiacial lines. The drift is comx- 



