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CONTENTS. 



PAOE 



Introductory Letter, .......... xiii 



Introduction, being a Synopsis of Practical Results, and Narrative of Events, . . . xvii 



CHAPTER I. 



Description op the Geological Formations op the Upper Mississippi, belonging to the 

 Silurian Period, lying between the Great Lead Region, south of the Wisconsin River, and 

 the Falls of St. Anthony, on the north, and from the Falls of the eastern tributaries of the 

 Mississippi Paver on the east, towards the sources of its western confluents on the west; treated 

 of under the following heads, . . . . . . . .41 



FORMATION I. 



Lower Sandstone of the Upper Mississippi, . . . . . . .48 



Sect. I. Its Lithological Character and Geological Aspect, illustrated by Wood-cuts, . . 48 



Sect. II. Its Palasontology, illustrated by medal-ruled Steel-Plate Engravings, from the original 



specimens, . . . . . . . . . .50 



Sect. III. Its Mineral Contents, . . . . . . . .53 



Sect. IV. Its Physical and Agricultural Character, illustrated by Wood-cuts, . . .55 



Sect. V. Its Range, Extent, and Bearing, illustrated by Sections and Map, . . .57 



Sect. VI. Its Local Details, . . . . . . . . .58 



FORMATION II. 

 A, B, C. 



Lower Magnesian Limestone op the Upper Mississippi, . . . . .58 



Sect. I. Its Lithological Character, and Geological Aspect, illustrated by Wood-cuts, . . 58 



Sect. II. Its Paleontology, illustrated by Steel-Plate Engravings, . . . .GO 



Sect. III. Its Mineral Contents, . . . . . . . .00 



Sect. IV. Its Physical Features, and Agricultural Character, illustrated by Wood-cuts, . . G4 



Sect. V. Its Range, Extent, and Bearing, illustrated by Sections and Map, . . . 68 



Sect. VI. Its Local Details, ......... G9 



St. Peter's Sandstone, .......... G9 



FORMATION III. 

 A, B, C. 



St. Peter's Shell Limestone, ........ 71 



Sect. I. Its Lithological Character, . . . . . . . .71 



Sect. II. Its Paleontology, illustrated by medal-ruled Steel-Plate Engravings, . . 73 



Sect. III. Its Mineral Contents, ........ 73 



Sect. IV. Its Physical and Agricultural Character, illustrated by Wood-cuts, . . 73 



Sect. V. Its Range, Extent, and Bearing, illustrated by Sections and Map, . . .70 



1* 



