C. R. Van Hise — Iron Ores of Michigan. 



123 



Fig. 1. Generalized section, showing relation of ore-deposits of Lower Marquette 

 series to associated formations. 



Fig. 2. Diagram showing tendency of an ore-deposit at contact of Lower and 

 Upper Marquette series, to send offshoots into the jasper parallel to its lamination. 



Fig. 3. Sharply plicated jasper (black belts) and ore (white areas), showing shat- 

 tering of the jasper and concentration of the ore. The ore is proportionally greater 

 where the folding has been the sharpest. Drawn from photograph. 



Fig. 4. Horizontal section of ore-deposit on east side of Republic horse-shoe. 

 Left side of ore bounded by a cross-joint ; right side is bounded in part by a sharp 

 flexure passing into a joint and in part grades into the lean banded jasper and ore. 



Fig. 5. Vertical section of an ore-body, bounded below by soapstone grading 

 into diorite, and above by ferruginous chert; change from ore to chert not so 

 sharp as drawn. 



Fig. 6. Another section of the same deposit shown in Fig. 5, but here is seen an 

 offshoot of soapstone from the main mass. 



Fig. 7. The ore upon left side rests upon soapstone g-rading into diorite and is 

 not at the contact plane of the Upper and Lower Mai'quette ; ore at right side is 

 at this contact plane and rests upon jasper. The two combined have a synclinal 

 appearance. 



Fig. 8. At the left the ore rests upon the soapstone grading into diorite ; at the 

 right it is upon one side of a dike-rock. The dike is an offshoot of the diorite. At 

 the contact of the two a trough is formed in which the ore-body becomes of large 

 size. Figs. 5, 6, 8 from mine plats furnished by Mr. Thompson. 



