XXXIV FISHES OF ILLINOIS 



Above its junction with the Yellow River the amount of water is 

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

 most 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 rang- 

 ing 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, bullrushes, sedges, reeds, wild rice, and other semiaquatic 

 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 year was quite regular and uni- 

 form 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, very rich in organic matter. 

 It is very porous, but has the power to take up and retain large quan- 

 tities of water. 



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

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

 mouth of the Iroquois to the head of the Illinois, the Kankakee falls 

 103 feet, or an average of 3 feet to the mile. There are rapids near 

 Altorf atnl at Wilmington, where sudden descents of 20 feet are 

 nude. In Indiana, as stated above, the bed of the river is com- 

 posed mainly of sand and fine gravel, but at Momence it begins to 

 (low over limestone, and from that point to its mouth it has a rock 

 1 >ni 1 1 iin, affording good foundations for dams for utilizing water- 

 power and f<T | turpi ises of navigation. The inner valley of the river is 

 but little wider than the stream, and outside this there is a broad 

 bottom averaging about 2 miles in width. 



