CONTENTS 



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Maps 



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 Regional Map of the Great Lakes 



1. — Geological Map of the Great Lakes Region 12 



2. — Glacial Map of North America 20 



3. — Glacial Map of the Great Lakes Region 22 



4. — First of the Glacial Lakes — Maumee and Chicago 32 

 5. — Glacial Lakes Maumee, Saginaw, Chicago, and 



Jean Nicolet 36 



6. — Diagram Showing Water Levels of the Various 



Stages of Lakes in the Erie Basin 38 



7. — Glacial Lakes Arkona and Chicago 40 



8. — Glacial Lakes Whittlesey, Saginaw, Chicago, 



AND Newberry 42 



9. — Glacial Lakes Warren, Chicago, and Duluth 48 



10. — Glacial Lakes Elkton (formerly Lundy), 



SiMcoE, Chicago, and Duluth 50 



11. — Glacial Lakes Duluth, Chicago and early 



Algonquin; Independent Lake Erie 52 



12. — Diagram of Niagara River Gorge 54 



13. — Glacial Lakes Algonquin and Iroquois; Lake Erie 56 



14. — Glacial Lakes Algonquin and Iroquois; Lake Erie 60 

 15. — Final Stage of Glacial Lake Algonquin; Lake 



Erie and Lake Iroquois 68 



16. — Nipissing Great Lakes, Lake Erie and Lake Ontario 70 



Photographs 



1. — "Pictured Rocks" Rampart of Cambrian Sandstone 15 



2. — Falls of Tahquamenon River 16 



3. — Beach on Mackinac Island 30 



4. — Arch Rock, Mackinac Island 64 



5. — Sugar Loaf Rock, Mackinac Island 65 



6. — Pointe Aux Barques, Sea Caves and Arches 66 



7. — Castle Rock, St. Ignace, Michigan 71 



8. — The "Fortress" of the Pictured Rocks 72 



9. — Cliff and Sea Cave 72 



10. — Stacks and Sea Caves 73 



11. — Chapel Rock 74 



12.— Wave-Cut Cliffs 74 



13. — Miner's Castle 75 



14. — Grand Marais Dunes 76 



15. — Nla-Gara Falls 80 



