XXXVlll FISHES OF ILLINOIS 



Kankakee falls 103 feet, or an average of 3 feet to the mile. 

 There are rapids near Altorf and at Wilmington, where sudden 

 descents of 20 feet are made. In Indiana, as stated above, the 

 bed of the river is composed mainly of sand and fine gravel, 

 but at Momence it begins to flow over limestone, and from that 

 point to its mouth it has a rock bottom, affording good founda- 

 tions for dams for utihzing water-power and for purposes 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. 



IROQUOIS RIVER 



Iroquois River is the chief tributary of the Kankakee in this 

 state. It rises in Jasper county, Indiana, flows southwest until 

 it reaches the center of Iroquois county, Illinois, and then turns 

 north, emptying into the Kankakee at Waldron, Kankakee 

 county. It is about 87 miles long and has a watershed of 2,175 

 square miles, much of which is imperfectly drained. Fully 

 935 square miles, or nearly half the basin, lies in Indiana. This 

 part is of the same type as the Kankakee basin, marshy and 

 sandy. Just before the river reaches Watseka, Illinois, it 

 crosses the Iroquois . moraine, and then traverses what was 

 probably once a temporary lake-bed. Sand banks, like those 

 along the Kankakee, foflow its valley. 



It is a much slower stream than the Kankakee in Illinois. 

 For the first 12 miles in this state it falls only about two and a 

 half feet per mile. Below Watseka it descends still more 

 gradually, falling only 10 feet in the first 20 miles and another 10 

 feet in the last 9 miles of its course. The Iroquois is about half 

 the size of the Kankakee above its junction. Although it rises 

 in the swamp region, it drains a much greater proportion of dry 

 prairie land than the Kankakee, and therefore is, comparatively, 

 a ''flashy" stream. Its freshets rise sooner, and they pass off 

 before those of the main river. In the region around Oilman, in 

 the western part of the basin, are many artesian wells which 

 add materially to the flow of the river in ordinary low water. 



ILLINOIS RIVER 



Measured by its relation to their industrial and civic in- 

 terests, the Illinois is by far the most important river to the 

 citizens of this state. Larger streams flow along our boundaries, 

 but none affects so closely the welfare of so man}^ of our people. 

 Indeed, from its peculiar position and its relation to other 



