THE CHICAGO OUTLET. 419 



discussed, but the outlet is not described. A map accompanying the paper 

 shows the approximate extent of the old lake beyond its present limits from 

 the southern end northward some distance into Wisconsin and Michigan. 



chamberiin. — Prof. T. C. Chamberliii presented a brief discussion of the 

 beaches along the Wisconsin shore of Lake Michigan in the Geology of 

 Wisconsin, 1 which includes many important data concerning the shore 

 phenomena and an interpretation of the lake history. In the twenty years 

 which have elapsed since that report was published, the studies of the shores 

 of the Great Lakes have brought out a more complex history than had 

 been anticipated; hence the interpretation does not fully meet the case, 

 though it recognizes important fluctuations of lake level. 



Leverett. — Although, subsequent to the publications just noted, there have 

 been frequent references in geological literature to the southwestward outlet 

 and the ancient beaches, no publication especially devoted to them appeared 

 until 1888, when a paper was published by the present writer in the Trans- 

 actions of the Wisconsin Academy of Sciences. 2 This paper gives a 

 somewhat detailed account of each of the several beaches found south of 

 latitude 42° 30', the latitude of the line of Wisconsin and Illinois. It 

 contains but a brief reference to the outlet. 3 



cooiey. — Prof. L. E. Cooley, consulting engineer of the Chicago Drain- 

 age Commission, has published two papers which deal to some extent with 

 the Chicago Outlet. 4 The first paper discusses the outlet as a means for 

 improving the sanitary conditions at Chicago. The second paper deals 

 with it as an important line for navigation, and discusses the proper means 

 for obtaining the best results This paper contains a large amount of valu- 

 able data concerning the regimen of the Illinois and Des Plaines rivers. 



Marshall. — The report of the United States Army Engineers for 1890 

 contains much valuable material collected by Capt. W. L. Marshall con- 

 cerning the Chicago Outlet as a channel for navigation; also references to 

 earlier work by that organization. 



i Geology of Wisconsin, Vol. II, 1877, pp. 219-233. 



^The raised beaches at the head of Lake Michigan, by Frank Leverett: Trans, of Wisconsin 

 Acad, of Sciences, Vol. VII, 1883-1887, pp. 177-192. Published in 1888. 



3 It should be explained that the numerous typographical errors in the paper are due to the fact 

 that the writer had no opportunity to correct the proof. 



4 Water supplies of Illinois in relation to health : Report of the Illinois State Board of Health, 

 1889. Lake and Gulf Waterway. Private publication, 1891. 



