U. 8. GEOLOGICAL SURVEY 
PROFESSIONAL PAPER NO. 54 PL. XV 
A 
VEIN STRUCTURE, LEVEL 4, PORTLAND MINE. 
A Stope on No 5 Captain vein, showing width of ore. 
11. Stope on Nos. 4 and 5 Captain veins, showing wide sheeting, scarcely distinguishable from ordinary jointing. 
