The Antwerp and Fowler Belt.—Crosby. 237 
except those intimately associated with the hematite in the chlo- 
ritic rock ; and it is not apparent by what reactions the magnesia 
of the limestone, existing, probably, largely in the form of in- 
soluble silicates, is to replace the acid aluminous silicates of the 
granite, reducing the silica by fully forty per cent. Prof. 
Smyth seems, farther, to regard the ore as a replacement of 
limestone, although so intimately associated with and enclosed 
in the massive chloritic rock, which is interpreted as an altered 
Fic, 1.—A fragment of the chloritic rock, showing slickensides. Two-thirds 
natural size. 
phase of granite. The masses of crystalline calcite in the ore 
are certainly suggestive of inclusions of limestone; but it 1s 
important to remember that calcite is an exceedingly impor- 
tant secondary mineral of the basic eruptives, as witness the 
crystalline calcites of the cupriferous melaphyrs of Keweenaw 
point. 
Apparently, the chemical difficulties of Prof. Smyth’s thesis 
are insuperable; but we turn now to the consideration of his 
