THE TOPOGRAPHY AND HYDROGRAPHY OP ILLINOIS lv 



paratively thin over much of the basin, and the streams have 

 cut down into the underlying rocks at many points. The 

 country near the river is hilly and much broken, the valleys of 

 the streams having been excavated to a depth of 100 to 200 feet 

 below the general level of the uplands. 



Throughout its course Apple creek is a swiftly flowing stream. 

 In the first 11 miles of its course it drops 100 feet. For the rest 

 of the distance the fall averages about 5 feet to the mile. 



MACOUPIN CREEK 



Macoupin creek rises in northern Montgomery county and 

 flows southwest into the Illinois. It drains an area of nearly 

 1,000 square miles (Leverett), consisting of the greater portion 

 of Macoupin county and parts of Montgomery, Greene, and 

 Jersey counties. Its watershed is broad in the middle and tapers 

 toward either end, giving it a broadly ovate outline. The whole 

 of the basin lies within the Illinoisan drift area. With the 

 exception of the headwater portion, above Carlinville, the main 

 stream apparently has its course determined by a preglacial 

 line, there being a broad depression, deeply filled with drift, 

 through which the creek takes its course. The tributary streams 

 appear to be largely independent of preglacial lines. 



The basin is composed of gently rolling or nearly level 

 prairies, which occupy the highlands between the streams and 

 cover fully one third of the area, and of heavy belts of timber 

 which skirt the streams. The soil is of a black, peaty character 

 on the level prairies, becomes chocolate-brown on the more roll- 

 ing surfaces, and degenerates into a light ash-gray near the 

 streams. 



The creek is about 90 miles long, and drains 989 square 

 miles. Its fall is varied, some parts, as the lower 17 miles, having 

 a fall of only one and one half feet to the mile, and other parts 

 much more, as the four and one half miles just above this, the 

 fall in this distance being 30 feet. Above this point the average 

 fall is about 2 feet to the mile. The banks are high, in some 

 places rising to 100 feet. In a few places the banks recede from 

 the water's edge, leaving bottom-lands one half to one and one 

 half miles in width. 



KASKASKIA RIVER SYSTEM. 



The Kaskaskia River system drains a large part of southern 

 Illinois, its drainage basin covering an area of 5,830 square 



