CONTENTS. IX 



Chapter III. — The Lower Marquette series, by C. R. Van Hise — Continued. Va'c. 

 Section VI. — The Negaunec formation — Continued. 



The iron-ore deposits 391 



The ore horizons 391 



Origin of the ores 400 



Prospecting 40.5 



Chapter IV. — The Upper Marquette series 408 



Introduction, by C. R. Van Hise 408 



Section I. — The Ishpeming formation, by C. R. Van Hise 409 



The Cxoodrich quartzite 409 



Distribution, exposures, and topography 409 



Folding 410 



Relations to adjacent formations 411 



Petrographical character 411 



Macroscopical .' 411 



Microscopical 413 



Thickness 416 



The Bijiki schist 416 



Distribution, exposures, and topography 416 



Folding 417 



Petrographical character 417 



Macroscopical 417 



Microscopical 418 



Relations to adjacent formations 419 



Thickness 420 



Interesting localities of the Ishpeming formation 420 



Michigamme and Spurr 420 



Lake Michigamme area 423 



Boston and Dexter area 424 



Lake Corning area 425 



Ishpeming area 425 



Negaunee area 427 



Cascade area 429 



Goodrich-Saginaw area 430 



Mount Humboldt area 432 



Champion area 434 



Lake Michigamme area 436 



Republic area 436 



Klomanarea 439 



Northern Republic and Western troughs 439 



Section II. — The Michigamme formation, by C. R. Van Hise 444 



Distribution, exposures, and topography 444 



Folding 445 



Petrographical character 445 



Macroscopical 445 



Microscopical 448 



Relations to the underlying formation 452 



Thickness 452 



