CHARACTER OF THE ORES.
1. Manganite, or magnetic oxide of iron.—No mines have been developed of this ore; but it has been discovered on Lake Machigummi and on St. Clair Mountain. It seems to belong to the lower beds, and is naturally the last to be developed.
2. Red hematites, or anhydrous sesquioxide.—At all the working mines we meet with the two varieties, specular and micaceous ; and in most specimens can be detected dis seminated crystals of magnetic oxide, so that these ores are in fact a union of the two.
3. Brown hematites, or hydrated sesquioxide of iron.—These ores appear to occupy an extensive area, and to form part of the rocky structure of the region, but exist as the decomposition of the ores in situ.
The above are the principal ores of this region, the specular being included with the red hematites. That these ores are sedimentary deposits cannot be doubted: they not only exhibit a perfect stratification, but present anticlinal and synclinal axes and folds which could not exist in beds or veins of igneous origin. Another conclusive fact is,
that much of the specular ore contains fragments of angular jasper in the shape of breccia, evidently the disintegrated portions of trappean rocks which were precipitated with the ores when the molten mass was thrown into the surrounding waters, proving that these accumulations of ore-beds and intercalated schist owe their origin 'to local causes, or that they are not the results of distant formations, but that they are true beds formed by the flow of molten lava highly impregnated with iron into the waters that existed around and perhaps over the volcanic vents, as described in the commence ment of this chapter.