SIXTH ANNUAL MEETING 21 



deposits, have been found also in the Chicago deposits of an 

 earlier date, showing: that tlie migration of life was principally 

 by way of the Chicago outlet. 



Dr. Pepoon is working on a survey of the plant ecology 

 of To Daviess and Fulton counties in comparison with that of 

 Cook county. With a list of 1.400 species for Cook. 950 for 

 Jo Daviess, and 1.000 for Fulton, he finds about 50 per cent of 

 the plants common to all three counties. Ten per cent of those 

 of Jo Daviess, 13 per cent of the Fulton county species, and 

 20 per cent of those of Cook, are not found in the other two 

 counties. 



From a study of some 1.800 collection of the Algae of east- 

 ern Illinois made by Dr. Transeau during the last five years, 

 he finds that our Algae may be divided into seven groups of 

 markedly different periodic habit, and that, in opposition to 

 the current view, they here fruit most abundantly during high- 

 water stages. A list of the Algae of eastern Illinois, contain- 

 ing notes on 245 species and varieties, has been prepared, and 

 will be submitted for publication in the Academy proceedings. 

 Twelve of these species are undescribed. and 23 of them have 

 not previously been collected in Xorth America. It is an 

 especially interesting fact that almost all of these new forms 

 have been collected in remnants of four old prairie ponds, all 

 threatened with extinction within a few j-ears. — an illustra- 

 tion of the importance of prompt and rapid work on represen- 

 tative relics of the original system of ecological association still 

 remaining in this state. The preparation of descriptions oi 

 of the plant associations of the Charleston area is progressing, 

 but is not yet complete. The succession of such associations 

 has been determined, a list of the prairie plants is nearly fin- 

 ished, and a list of the forest plants is well under way. 



Mr. Hankinson is still working upon the ecological bi- 

 ology of the streams of his area, and has also made many 

 notes, collections, and photographs illustrating the life of the 

 woodlands and of the open fields. The invertebrates of his 

 collections are being distributed for determination, and his 

 data relating to fishes are being made ready for publication. 



The work of the natural history survey of the state, is in 

 progress under the State Laboratory of Natural History, has 

 been limited during the past year to further studies of the 

 biological system of the Illinois River as affected by seasonal, 

 hydrographic, and chemical conditions — but especially by con- 

 tamination factors introduced by way of the sanitary canal of 

 the Chicago district: and to the preparation of a final report 

 on the statistical survey of the bird life of the state already re- 

 ferred to. 



