INDEX. 



XI 



age of schists, 24 ; prc-PotsJam age of 

 sandstone, 90. 



Wichniann, .\., diorite of, 37; on eclogite, 

 48 ; on feldspar crystals, 44 ; limits be- 

 tween jasper and ore, 33 ; on olivine-dia- 

 base, 70; on the Presqiie Isle serpentine, 

 62 ; report on the rocks of the iron dis- 

 trict, GO ; Hse of tei'ni qnartzite, 58, oV) ; 

 originally formed products in feldspar, 55, 

 5G. 



■Winchcll, X., on the iron district, 17, 18; 

 sediiuentarv origin of iron ores and dio- 

 rites, 17, 1*8. 



Wisconsin geologists, defective methods of, 

 107, lis ; on the Kewecnawan series, 107. 



Wright, C. E., metamorphie origin of gran- 

 ite, 25; origin of "soft luinalite," 25; 

 relation of Laurentian and Hiironian, 25 ; 

 salt cubes in quartz, 25, 5(5 ; sedimentary 

 origin of iron ore, 25 ; unity of foliation 

 and stratification, 25. 



Zeolites, formation of, 91, 93. 



Zircon crystals in quartz and feldspar, 56 ; 



in granite, 57 ; microlitcs of, in quartz, 



57, 59. 

 Zirkel, Ferdinand, " inserted substance " a 



base, 37 ; originally formed products in 



feldspar, 55, 56. 



e> 



