VI 



REPORT OF STATE GEOLOGIST. 



THE GEOLOGY OF LAKE AND PORTER COUNTIES. 

 BY W. S. BLATCHLEY. 



PAGE. 



GENERAL PHYSIOfiRAPH Y 25 



TU E UNDERl A'lNG ROCKS 27 



The Black or Genesee Shale 27 



The Lower HelderbergLimestone " 28 



The Niagara Limestone 29 



GLACIERS AND GLACIAL DEPOSITS 29 



Origin of Glaciers 30 



Glacial Epochs 30 



A. Terminal Moraine 31 



The Valparaiso Moraine 32 



Formation of Lake Chicago 32 



Area of Lake Chicago 33 



THE CALUMET OR NORTHERN REGION 33 



The Upper or Glenwood Beach 33 



The Middle or Calumet Beach . , 35 



The Lower or ToUeston Beach 36 



Low Beaches » 37 



The Present Beach 38 



The Sand Dunes 39 



The Sand Supply 41 



The Calumet Eiver 41 



THE MORAINIC OR MIDDLE REGION 43 



The Moraine in Lake County 43 



The Moraine in Porter County 45 



Morainic Lakes 49 



The Water Shed 53 



Drainage 53 



KANKAKEE OR SOUTHERN REGION 55 



The Kankakee Riter *. 55 



The Kankakee Marshes 57 



Origin of Kankakee Valley 59 



Drainage of the Kankakee Marshes 60 



GENERAL FEATURES 65 



Prairies 65 



Farm Products 67 



Mineral Products 70 



Railways 76 



Wolf Lake Harbor 79 



Archaeology 82 



Notes on the Fauna of Lake and Porter Counties 89 



Notes on the Flora of Lake and Porter Counties 92 



Elevations • 103 



V 



