LIST OF ILLUSTRATIONS. 



FROM ORIGINAL SKETCHES IN THE FIELD.* 



WOOD-CUTS. 



PAGE 



Gorge and Falls of Pigeon River : engraved by W. Roberts ; on wood by C. E. Dopier, Frontispiece. 

 Dike of Columnar Basalt, Grand Portage Bay, Lake Superior : engraved by Richardson & Cox : 



on wood by S. Wallin, ........ vignette. 



La Pointe and Bay of Madeline Island, Lake Superior: engraved by N. Orr; on wood by C. Gil- 

 den meister, ........... 34 



Natural Section of Bluffs of Lower Palaeozoic Rocks : drawn and engraved on wood by J. W. 



Louderback, .......... 40 



Cliff of Lower Magnesiau Limestone, Plum Creek : drawn and engraved on wood by J. W. 



Louderback, .......... 42 



Outcrop of Lower Sandstone, Kickapoo : engraved by R. Teller ; on wood by J. B. Howell, . 4o 

 Hill of Alternations of Lower Sandstone and Maguesian Limestone: engraved by R. Telfer j on 



wood by A. Lawrie, . . . . . . . . .43 



Outlet of Lake Pepin : engraved by D. C. Baxter; on wood by L. Elliot, . . .44 



Cap des Sioux, Lake Pepin: engraved by R. Telfer; on wood by A. Lawrie, . . .45 



La Grange Mountain : engraved by Richardson & Cox; on wood by S. Walliu, . . .46 



Amphitheatre of Sand : engraved by A. Sollin ; on wood by Devereux, . . . .55 



Alternations of Lower Sandstone and Magnesian Limestone, Iowa River; engraved by G. A. Hoff- 

 man ; on wood by W. Croome, . . . . . . . .57 



Castellated Appearance of Lower Magnesiau Limestone, Iowa River : drawn and engraved on wood 



by Devereux, .......... 65 



Natural Wall and Bastions of Lower Maguesian Limestone, Iowa River : engraved by A. Sollin ; 



on wood by Devereux, ......... 66 



Northern and Southern Slopes : engraved by R. Telfer ; on wood by A. Lawrie, . . .67 



Cliffs of Lower Magnesian Limestone, Iowa River; engraved by W. B. Gihon ; on wood by W. 



Croome, ........... 68 



Natural Wall of Sandstone, Kinnikinick : drawn and engraved on wood by J. W. Louderback, 



after a Sketch by Lewis, ......... 70 



Remarkable Outline of Hills on Turkey River: engraved by E. P. Vollum; on wood by C. E. 



Dopier, ........... 74 



Outcrop of Upper Magnesiau Limestone and Shell-beds, Turkey River ; engraved by G. A. Hoff- 

 man; on wood by Devereux, . . . . . . . .75 



Outcrop of Limestone on Shell Rock : drawn and engraved on wood by J. W. Louderback, . 78 



Region of Drift, Prairies of Northern Iowa : engraved by N. Orr ; on wood by C. Gildenmeistcr, 80 

 View on the Upper Iowa : drawn and engraved on wood by J. Orr, . . . .88 



Concretions in Muscatine quarries : drawn and engraved on wood by W. B. Gihon, . . 100 



Outline of Carboniferous Limestone, Upper Iowa : engraved by Bobbett & Edmonds ; on wood by 



Beckwith, ........... 101 



* Except when otherwise designated, by D. I>. Owen and Richard Owen. 



