MUSSEL FAUNA OF THE KANKAKEE BASIN. 



29 



duced, and would produce shells that bring large sums of money in 

 the market. The hunting and fishing would not be injured, but 

 rather benefited by the increase of the mussels. 



Here is an ideal chance for the breeding of mussels on a large 

 scale; it only needs to be once started to prove its value. Further- 

 more, the mussels are infested with the same kinds of parasites as 

 those of the Yellow Eiver, while pearls and baroques are even more 

 plentiful. Consequently, the prospects of a reasonable bonus from 

 this source are exceptionally good. 



Station 23. Kankakee River hetween the State line and Momence^ 

 III. — Just across the State line occurs the first limestone outcrop in 

 the bed of the river. This is the ledge which has acted as a natural 

 dam and prevented the wearing down of the river bed. Were it not 

 for this ledge the river would have long since drained the immense 

 swamp region. But just as it is responsible for the character of the 

 channel above it in Indiana, so it marks the beginning of a very dif- 

 ferent kind of channel below it in Illinois. In the 50 miles of river 

 from the State line to the head of the Illinois, the Kankakee falls 

 130 feet, or nearly 3 feet per mile. From a deep and smoothly mov- 

 ing river, without a break between its source and the State line, it 

 is suddenly converted, on passing this ledge, into a succession of 

 broad and shallow rapids difficult to navigate. The old bed of sand 

 and fine gravel ceases and in its place we find shelving rocks, coarse 

 gravel, and bowlders. 



Such radical changes in the surrounding conditions would suggest 

 that the mussel fauna must change also, and such we find to be the 

 case. Several additional species appear all at once and are common 

 down to the mouth of the river. We no longer find a continuous bed 

 of mussels, but they are scattered wherever they can find a foothold. 

 For long distances the solid rocky bottom prohibits them from re- 

 maining; then come favorable localities where they are packed as 

 I closely together as they can lie. In general, the conditions are not 

 ! as favorable in Illinois as in Indiana ; it is certainly very much more 

 difficult to gather the mussels. Our first collection within the State, 

 however, was made rather easy by the fact that pearlers had been 

 I at work along the river and had left small piles of shells scattered 

 I here and there on the banks. We selected from these and supple- 

 , mented them with living specimens of other species. Near the State 

 line some undulata were found with a yellowish epidermis instead 

 of black. 



Station 2J{.. Momence^ III, — Just above the town was the camp of 

 three mussel fishermen who had been collecting shells from the im- 

 mediate vicinity for the market. They had secured about 15 tons, the 

 only culls from which were a few U. gihhosus. They told us the 

 shells from this locality were not as tough as those in the Wabash 



