CONTENTS. XI 



Chapter VI. — The Republic Trough, by Henry Lloyd .Smyth — Continued. j.,|„„ 



Section II. — The Lower Marquette series 528 



The Ajibik quartzite 528 



The Negaunee formation 529 



Contacts between the Lower Marquette series and the Archean 532 



Section III. — The Upper Marquette series 535 



Contacts of the Goodrich quartzite with the Lower Maniuette series and with the 



Archean g3g 



Section IV. — Later igneous intrusives 538 



Section V.— General geology 538 



Faults 54,1 



The ore deposits 547 



Position of the ore deposits 547 



Relations of the ore deposits to the geological structure 549 



Origin of the ore deposits 551 



Chapter VII. — General geology, by C. R. Van Hise 554 



The Basement Complex 555 



The Lower Marquette series 556 



The transgression horizon 556 



Unconformity at the base of the Lower Marquette series 557 



Deposition of the Lower Marquette .series 559 



Eruptives of Lower Marquette time 562 



Unconformity at the top of the Lower Marquette series 562 



The Upper Marquette series 563 



Deposition of the Upper Marquette series 563 



Folding of the Basement Complex, Lower iSIarquette series, and Upper Marquette series .1()6 



Intrusives 571 



Denudation 572 



Metamorphism 573 



Correlation 575 



Index 58o 



