Pleistocene Features and Deposits of the Cliicago Area. 



By FRANK LEVERETT. 



INTRODUCTORY STATEMENT. ■ 



The Chicago area here discussed embraces not only the site 

 of the city, but adjacent territory west and south, nearly to the 

 Fox and Kankakee Rivers, and north nearly to the line of Illinois 

 and Wisconsin. It is made to include the first great moraine which 

 sweeps around the head of Lake Michigan, as well as several weak 

 morainic lines lying nearer the lake. It includes also the ancient 

 beaches of Northeastern Illinois and a portion of the outlet of 

 the body of water which formed them. It is a countiy exception- 

 ally full of varied and interesting features. 



Some of the features, especially those pertaining to the old 

 lake and its outlet, are discussed by Dr. Edmund Andrews, in an 

 early volume of the Transactions of the Chicago Academy (i). 

 The same features and some of the leading features of the glacial 

 deposits were briefly discussed by Dr. H. M. Bannister, in his 

 ofificial reports to the State Geologist (2). A description of the 

 principal moraine traversing this district, based upon studies by 

 Prof. T. C. Chamberlin and Prof. L. C. Wooster, is given by Pro- 

 fessor Chamberlin in an early report of the United States Geolog- 

 ical Survey (3) 



The paper which follows aims to discuss these features in the 

 light of a somewhat detailed study of Pleistocene deposits, which 

 I have had the privilege of making in this and adjacent districts. 

 Carried on as this study 'has been, under the direction of Prof. T. 



n) The Norf-.h American Lakes considered as Chronometers of Post glacial 

 lime. By Dr. Edmnnd Andrews, Transactions of The Chicago Academy of 

 Sciences. Vol. 11. ]R70, pp. 1-23. 



'2) Geology of Cook County. By H. M. Bannister. Vol. III. 1868. pp. 239-244. 

 rc„„^*^"'°^y o^ -DeKalb. Kane and DuPage Counties. By H. M. Bannister. Vol. IV, 

 1870, pp. 111-113. 



geology of McHenry and Lake Counties. By Dr. H. M. Bannister. Ibid, pp. 



-D mil P';ftliminary Paper on the Terminal Moraine of the Second Glacial Epoch. 

 By ihos. C. Chamberlin, Third Annual Report, IT. S. Geol. Survey, 1881-82, pp. 322-325, 



