XIV LIST OF ILLUSTRATIONS 



PAGE 



Fig. 25. — ^A Dyke near Marquette, Michigan 39 



Fig. 26. — A Monadnock, Ishpeming, Michigan 40 



Fig. 27. — Rocks Folded and Crumpled, Jasper and Hematite, 



Ishpeming, Michigan . . . . . . . .41 



Fig. 28. — Map of Surface Rocks, Illinois, Wisconsin, Michigan . 43 

 Fig. 29. — A Coral Reef Exposed at Quarry, Thornton, Illinois, 



Showing the Concentric Lines of Deposit ... 45 

 Fig. 30. — Map Showing Land and Sea When Potsdam Sandstone 



Was Depositing (Upper Acadian), after Schuchert . 47 

 Fig. 31. — Map Showing Land and Sea When Magnesian Limestone 



Was Depositing (Beekmantown), after Schuchert . . 47 

 Fig. 32. — Map Showing Land and Sea When Richmond Shales Were 



Depositing (Cincinnatian), after Schuchert ... 47 

 Fig. 2>Z- — Map Showing Land and Sea When a Part of the Niagara 



Limestone Was Depositing (Mid-Silurian), after 



Schuchert 47 



Fig. 34. — Animal Fossils from Niagara Limestone .... 49 

 Fig. 35. — Map of the Late Paleozoic When the Illinois Coal Beds 



W^ere Depositing (Upper Pennsylvanian) , after Schuchert 5 1 

 Fig. 36. — Fossils of the Coal Period from Mazon Creek, Illinois . 53 

 Fig. 37. — The Great Arch of Rocks in Illinois, a Diagram ; . . 54 



Fig. 38 



Fig. 39 



Fig. 40 



Fig. 41 



Fig. 42 



Fig. 43 



Fig. 44 



Fig. 45 



Fig. 46 



Fig. 47 



Chapter IV 



-Glacial Map of North America 57 



-Conjectural Preglacial River System 58 



-Angular and Striated Glacial Bowlder near Glencoe, 



Illinois 60 



-Grooves and Scratches on Bed Rock at Stony Island Due 



to Glacial Erosion 61 



-Map of JNIoraines in the Chicago Region . . . . 62 

 -Map of Moraines in Illinois, from Bulletin State Geological 



Survey 65 



-View of Typical Glacial Country a Few Miles Southwest 



of Chicago 66 



-Flathead, below Joliet, General View and Detail . . 67 



-Figures of Several Crystals 68 



-Cleavage Shown in a Piece of Orthoclase Feldspar . . 69 



Chapter V 



Fig. 48. — The Wisconsin Ice Sheet at Its Maximum Extension . 79 

 Fig. 49. — An Old Shore Line of Lake Chicago 80 



