PLATE B. 



EXPLANATION. 



Figure 1. Labradorite feldspar, from Beaver Bay p. 147 



Magnified forty diameters. No. 8 of the systematic table. 

 Figure 2. The same between crossed Nicols. 

 Figure 3. Bed quartzyte from Pipestone county p. 153 



Magnified forty diameters. No. 12 of the systematic table. 

 Figure 4. The same between crossed Nicols. 

 Figure 5. Dolomite from Frontenac p. 155 



Magnified forty diameters. No. 13 of the systematic table. 

 Figure 6. Dolomite from Stillwater p. 155 



Magnified forty diameters. No. 14 of the systematic table. 



