THE GEOLOGICAL SURVEY. 



The Board of Management of the Geological and Natural 

 History Survey take pleasure in presenting the second of its 

 proposed publications, a list of which may be found on the 

 fourth cover page. 



The history and aims of the survey are outlined in the 

 first bulletin, The Lichen Flora, prepared by Mr. W. W. 

 Calkins, and published through the generosity of Mr. Albert 

 Dickinson. It is only necessary, therefore, to repeat here the 

 extent of the territory covered by the survey. This area 

 comprises Cook and Du Page Counties, and the nine north 

 townships of Will County, in Illinois, and a portion of Lake 

 County, Indiana, giving a surface of about forty-eight or fifty 

 miles square, or a land surface of nearly 1800 square miles. 



The present bulletin on the Pleistocene Features and 

 Deposits of the Chicago Area, has been prepared by Mr. 

 Frank Leverett, of the U. S. Geological Survey. The Board 

 desires to express its appreciation of the time and labor that 

 must have been taken from the stress of other duties in the 

 preparation of this very creditable work as well as of the 

 assistance given to Mr. Leverett by individuals and institu- 

 tions, recognition of which has been made in the body of 

 the text. 



The Board wishes further to make acknowledgement of 

 the courtesy extended by the Sanitary District of Chicago, 

 which, through the kindness of Mr. T. T. Johnston, Assistant 

 Engineer, prepared the maps and profiles from Mr. Leverett's 

 manuscript copy. 



All into whose hands this bulletin may come, will join 

 with the members of the Board in appreciation of the gener- 

 osity of Mr. George Laflin, whose prompt response to the 

 request for funds to publish the bulletin is but another' 

 instance of the liberality which has marked his attitude 

 towards the Chicago Academy of Sciences. 



The Board. 



