FISHES OF ILLINOIS 



Sangamon. The stream is about 60 miles long and drains an area 

 of 1,400 square miles (Leverett). Its watershed 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 dis- 

 tant less than five miles. No important tributaries enter from the 

 west, but several creeks lead into it from the east which have lengths 

 of IS to 20 miles or more. These eastern tributaries present a re- 

 markable parallelism, 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 sub- 

 glacial stream. Shallow channels may also have been opened by 

 the same agency along the other eastern tributaries and have 

 occasioned their remarkably direct and parallel courses (Leverett). 



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 deter- 

 mined by a preglacial drainage line, but elsewhere the drainage ap- 

 pears to be nearly independent of preglacial 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 500 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 45 miles long. 



The entire basin lies within the Illinoisan drift. The lower course 

 of the river seems to be along the line of a preglacial valley, but 

 the headwater portion and also a majority of the tributaries show 

 little dependence upon preglacial lines. The drift is comparatively 

 thin over much of the basin, and the streams have cut down into 



