CONTENTS. 



Page. 



Introductory Statement 9 



Outline of Time Eelations or Glacial Succession. 11 



Albertan, or Oldest Recognized Drift Sheet 13 



Aftonian Interval of Recession or Deglaciation 13 



Kansan Drift Sheet of the Iowa Geologists 14 



Second Interval of Recession or Deglaciation 14 



Iliinoian Drift Sheet • 14 



Third or Pre-loessial Interval of Recession or Deglaciation 15 



lowan Drift Sheet and Main Loess Deposit : 16 



Fourth or Post-loessial Interval of Recession or Deglaciation 16 



Early Wisconsin Drift Sheets 17 



Shelby ville Morainic System 17 



Champaign Morainic System 18 



Bloomington Morainic System 19 



Marseilles Morainic System 20 



Fifth Interval, shown by Shifting of Ice Lobes 20 



Late Wisconsin Drift Sheets 21 



Great Bowlder Belts and Accompanying Moraines 21 



Valparaiso Morainic System 22 



Lake-Border Morainic System 22 



The Lake Beaches 22 



General Physiographic Features of the Chicago Area 23 



The Valparaiso Moraine in Illinois 26 



The Moraine 26 



Distribution 26 



Relief 27 



Surface Contours 28 



Thickness of Drift 29 



Structure of Drift 31 



Flowing Wells 37 



Palatine Flowing Well District. 37 



Salt Creek Flowing Well District 38 



Outer Border Phenomena 38 



The Lake-Border Morainic System 42 



The Moraines 42 



Outer, or West Ridge 42 



The Middle Ridge 42 



The East Ridge 43 



Relief 43 



Thickness of the Drift 44 



Structure of the Drift 44 



