4  CONTENTS. 
Page. 
Chapter  III.  Lake  Superior  region 108 
Section  1.  Michigan 108 
Summary  of  literature , 108 
Section  2.  Northern  Wisconsin 178 
Summary  of  literature 178 
Section  3.   Minnesota 196 
Summary  of  literature 196 
Section  4.  Part  of  Ontario  northwest,  north,  and  northeast  of  Lake 
Superior 253 
Summary  of  literature 253 
Section  5.  Lake  Superior  region  (general) 298 
Summary  of  literature 29S 
Section  6.  Summary  of  present  knowledge  of  Lake  Superior  region 327 
Introduction 327 
Archean  system,  or  basement  complex 33J 
Michigan  and  Wisconsin * 332 
Central  and  eastern  Minnesota 333 
Mesabi  district 333 
Vermilion  district 333 
Lake  of  the  Woods  and  Rainy  Lake 334 
Michipicoten  district . 335 
Other  points  on  the  north  shore 335 
Algonkian  system 335 
Huronian  series 335 
Marquette  district 335 
Crystal  Falls  district 336 
Menominee  district 337 
Penokee-Gogebic  district 337 
Iron  River  and  vicinity . 338 
Northeastern  Wisconsin 338 
North-central  Wisconsin 338 
Chippewa  River  and  Barron  County 338 
Central  Minnesota 338 
Mesabi  district 339 
Vermilion  district 339 
Rainy  Lake 340 
Steep  Rock  Lake 340 
Hunters  Island  and  region  northwest,  north,  and  north- 
east   340 
International   boundary   and   north    shore   of    Lake    Su- 
perior   341 
Michipicoten  district 341 
Keweenawan  series 341 
Distribution 341 
Succession 342 
Lower  Keweenawan , 342 
Middle  Keweenawan 343 
Igneous  rocks .    343 
Sedimentary  rocks 344 
Upper  Keweenawan , 346 
Structure 346 
Thickness 347 
Copper  deposits ^_,_, ,, „______  347 
