XIV ILLUSTRATIONS, 



Page. 



Plate XX. Fi<;. 1. Ferruginous chert, from Taylor mine 346 



2. Ferruginous chert, from south of Jackson mine, sec. 1, T. 47 N., R. 27 W 346 



XXI. Hematitic chert, from Negaunee 348 



XXII. Hematitic cliert, from Negaunee 350 



XXIII. Maguetitic chert, from the Michigamme mine 352 



XXIV. .laspilite, from the Grand Rapids mine, Negaunee 354 



XXV. .laspilite. from Jasper bluff, Ishpeming 356 



XXVI. Fio. 1. Folded j.aspilite, from Jasper bluff, Ishpeming 358 



2. Brecciated jaspilite, from Jasper bluff, Ishpeming 358 



XXVII. Fig. 1. Jaspilite, from Jackson mine, Negaunee 360 



2. Ore and jasper conglomerate, from north of Lowthian mine 360 



XXVIII. The ore deposits 394 



XXIX. The ore deposits 398 



XXX. Goodrich ijuartzite with minor fold cut by dike, Michigamme mine 410 



XXXI. Conformable exposure of Goodrich quartzite and Bijiki schist, with grada- 

 tion zone between, near Michigamme 412 



XXXII. Fk;. 1. Thin section of sedimentary bed, from Clarksburg formation, showing sec- 

 ondary hornblende crystals 470 



2. Thin section of fragmental rock, from near base of Clarksburg formation.. 470 



3. Thin section of banded tuff, from Clarksburg formation 470 



4. Thin section of greenstone, from Republic, showing secondary hornblende 



crystals 470 



XXXIII. Sketch map of the dikes of Mount Humboldt 508 



XXXIV. Geological map of the southeast end of the Republic Hor.-ieshoe 546 



XXXV. Fig. 1. A pitching fold in Siamo slate, sec. 21, T. 47 N., R. 27 W 570 



2. Fan fold in ferruginous schist 570 



FIGURES IN THE TEXT. 



Fig. 1. Generalized cross-section of Marquette synclinorium, showing the Marquette type of 



fold 4 



2. Horizontal section of ore bodies at the surface of the Champion mine 95 



3. Cross-section through ore bodies at the Edwards mine 96 



4. Cliff of Kitchi schist, in sec. 33, T. 48 N., E. 27 W 161 



5. Outlines of plagioclase grains, in nonconglomeratic band of Kitchi schist 165 



6. Magnetite in fine-grained diabase or basalt 180 



7. Mica-schist intruded by granite, south of Champion mine 193 



8. Thin section of feldspathic biotite-schist, from sec. 3, T. 47 N., R. 30 W 197 



9. Cleavage in slate between two limestone beds 243 



10. Reibungsbreccia in cherty quartzite truncating limestone strata 243 



11. Basal conglomerate of Wewe slate, from near center of sec. 22, T. 47, N., R. 26 W 259 



12. Shattered slate cemented by vein quartz, from northeast quarter sec. 21, T. 47 N., R. 26 W 263 



13. Brecciated slate cemented by vein quartz, from same locality as fig. 12 263 



14. Ajibik quartzite resting unconforraably upon Kitchi schist 296 



15. Minor overturned folds in Siamo slate 315 



16. Relations of schistosity and beddiug iu Siamo slate 315 



