O. S. GEOLOGICAL SURVEY 
BULLETIN NO. 293 PL. Ill 
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[To centimeters] 
i T^" r~r-r- _nzzi:.- 'r" i I -1 
.1. SPECIMEN OF TIN-BEARING PEGMATITE. 
B. PHOTOMICROGRAPH OF TIN ORE FROM THE JONES MINE. 
Showing the dark cassiterite as a constituent of the quartz-mica pegmatite. Magnified 20 diameters. 
