Article X. — Studies on the Biology of the Upper Illinois River. 

 By Stephen A. Forbes and R. E. Richardson. 



The Illinois River is peculiarly characteristic of the State of Illi- 

 nois, and, next to the prairies, was its leading natural feature. The 

 level richness of the central plateau of the state is reflected in the 

 turbid waters and the broad sluggish current of the stream; and 

 its wide bottom-lands, originally covered with huge trees, completely 

 flooded when the river is highest, and holding many marshes and 

 shallow lakes at its lowest stages, are a relic of the time, not so very 

 far remote, when the limpid waters of the Great Lakes rolled down 

 its valley in a mighty flood on their course to the southern gulf. It 

 was not an accident that this river was the first great artery of 

 transportation into and through the state, or that the first colonial 

 settlement and the first fortified post in Illinois were established on 

 its banks. After the railroads had deprived it of its commerce it 

 was discredited and neglected for many years, and the second city 

 in the country and the second city of the state have long used it as 

 a mere convenience for the discharge of their organic wastes. 



These are temporary conditions, however, and the time seems 

 now at hand when the people of Illinois will learn to appreciate and 

 develop this great gift of nature in the various directions in which 

 it may be made to serve their interests and their pleasures. Its fre- 

 quently beautiful and occasionally picturesque scenery is attracting 

 more attention every year; and when, as is sure to happen in due 

 time, a superior highway follows its course between Chicago and 

 St. Louis ; when the attractive building sites on its banks are re- 

 lieved, as they now might generally be, from the midsummer plague 

 of mosquitoes ; when its most interesting situations are converted 

 into public parks, and its fisheries are protected and enriched bv 

 means of state reservations for the breeding and feeding of fishes ; 

 and when, as must eventually come to pass, it becomes once more an 

 indispensable central link in a principal line of traffic between the 

 Great Lakes and the Gulf, — it will take for all time, for the state 

 at large, the place which Lake ^Michigan now holds for our greatest 

 city. 



The senior author of this report began work, as a biologist, on 

 Illinois River problems, some thirty-six years ago ; and the junior 

 author has virtually lived on the river for purposes of investigation 

 during the last four years. The Natural History Survey of the state 



