THE TOPOGRAPHY AND HYDROGRAPHY OF ILLINOIS XXXVll 



The basin of the Kankakee is generally level, but near the 

 state-line, at Momence, occurs the first limestone outcrop in 

 the bed of the river. This ledge or arch has so prevented the 

 wearing down of the bed that a very large part of the drainage 

 area in Indiana is one vast swamp. From its source to the 

 state-line there is a direct distance of onl}^ 75 miles, but within 

 this distance the stream makes 2,000 bends and flows a total 

 length of 240 miles. The difference in level between its source 

 and the state-line is but 97.3 feet, showing a fall of but 1.3 feet 

 to the mile. (Indiana Geological Survey.) The winding of 

 the river reduces the fall to onlj^ 5 inches to the mile. Above 

 its junction with the Yellow River the amount of water is in- 

 sufficient to form a well-defined channel. The water has an 

 almost imperceptible flow, and in many places wild rice, rushes, 

 lily-pads, and aquatic grasses so choke the channel as to cause 

 the flooding of the marshes during summer freshets. Below 

 this point, however, there is quite a definite open channel, 

 although the small tributaries are usually lost in the marsh 

 before reaching the main stream. On the immediate border of 

 the river there is a strip ranging in width from one fourth to 

 one and one half miles which is heavily timbered. The only other 

 timber is found on so-called islands whose surfaces rise 10 to 20 

 feet above the general level of the marsh. The open marsh is 

 covered with a rank growth of wild grasses, bulrushes, sedges, 

 reeds, wild rice, and other semiaq'uatic vegetation. Between 

 the woodland bordering the river-bank and the marsh, as well 

 as around the margin of most of the islands, there are dense 

 thickets of elbow-brush, willows, etc. In 1882 there were 

 almost 500,000 acres of marsh land within the valley of the 

 Kankakee. It resembled an immense sponge, slowly absorbing 

 the water during the wet season and as slowly giving it forth 

 during the dry, so that the flow throughout the 3'ear was quite 

 regular and uniform in amount. At present, on account of the 

 drainage of a large part of this marsh, the water flows off much 

 sooner after it falls, and consequently the river is higher during 

 the autumn and spring floods and lower at other seasons than 

 formerly. In general the soil of the marsh is a dark, sandy 

 loam, ver}^ rich in organic matter. It is very porous, but has 

 the power to take up and retain large quantities of water. 



In the 14 miles below Momence, 111., to its junction with 

 the Iroquois, there is a descent of 25 feet. In the 33.5 miles 

 from the mouth of the Iroquois to the head of the Ilhnois, the 



