18 



C. C. Adams presented a paper which is given below in 

 abstract. 



RECENT HABITAT CHANGES IN THE ILLINOIS 



RIVER. 



This paper is a report of an ecological reconnoissance of 

 the Illinois River at Havana carried on by the cooperation 

 of the State Laboratory of Natural History and the Ecolog- 

 ical Survey Committee of the State Academy of Science. 



During recent years the increased amount of water in the 

 river has raised the water level about 3 feet. This has sub- 

 merged the lowlands, killed many trees and produced numerous 

 changes in the animal habitats. The paper describes some of 

 the changes observed in 1909 and compares them with condi- 

 tions previous to the high water. 



A. R. Crook inquired concerning the cause of the sudden 

 changes in the height of water as shown by the "lily pads" left 

 standing and the changes in the amount of vegetation in the 

 waters of the region described, from year to year. 



C. C. Adams replied that Prof. Forbes could answer the ques- 

 tions. 



Mr. Forbes said that the cause of the changes were ex- 

 tremely complex and necessitated close study for a series of 

 years, study which was being prosecuted by the survey. 



JV. S. Strode. — "This paper touches me in a tender spot. The 

 Thompson lake region so ably portrayed is my old stamping 

 ground, and I have explored every foot of it. It is the richest 

 f aunal region in the state or anywhere else ; rich in shells, fishes, 

 birds, plants, aquatic life of all kinds. The turning in of the drain- 

 age ditch water a few years ago made a great change ; plants and 

 trees died ; there are hundreds of acres of dead trees all about 

 the lake. The lake is high water now all the time. A few 

 years ago one could wade across it. This lake at one 

 time during a very low period nearly caused the death of all 

 the unios or fresh water mussels it contained, almost car loads 

 of them indeed and windrows of the dead shells extended all 

 the way aroimd the lake, and it looked like the extinction of 



