. Transactions. from a megascopic examination of these rocks,and proven by a microscopic examination. A thin section of the speci-men of this rock, as stated in a previous part of the paper, shows it tobe impregnated with the sulphides, while in two sections which were ex-amined by the writer, fairly fresh pyroxene and orthoclase crystals werefound to contain inclusions of the sulphide, showing these minerals tohave been formed previous to and out of the same magma as the com-ponents of the greenstone. Vogt, in describing similar nickel de-posits in Norway, speaks af the sulphide as rock-formi
. Transactions. from a megascopic examination of these rocks,and proven by a microscopic examination. A thin section of the speci-men of this rock, as stated in a previous part of the paper, shows it tobe impregnated with the sulphides, while in two sections which were ex-amined by the writer, fairly fresh pyroxene and orthoclase crystals werefound to contain inclusions of the sulphide, showing these minerals tohave been formed previous to and out of the same magma as the com-ponents of the greenstone. Vogt, in describing similar nickel de-posits in Norway, speaks af the sulphide as rock-forming mineral, andbelieves them to have assumed their present form at the time ofsolidification of the rocks containing them. He calls such rocks, richin pyrrhotite, pyrrhotite-norites, and regards the ores to be the mostbasic rock constituent. He considers that the relation of the pyrrhotite-norite to the greenstone is similar to that which the basic borders I I The Sulphide Ore Bodies of the Sudbu7-y Region. 539. u 540 The Canadian Mifiitig Institute. on granite-stock hold to the granite ; both, he beUeves, were formedby the differentiation of a once homogeneous magma. Sandbergerseparated the dark siHcates of a great many rocks, and, by operatingon quantities of 30 grams, proved them to contain Cu, Ni, Co, Pb,Sn, Sb, As, Bi, and Ag, and considered them also to act as Vogts opinion, that the pyrrhotite-norite of Norway isrelated to the greenstone in the same way as the basic borders ongranite stock is to the granite, and that the Norway deposits tooktheir present form on solidification, appHes equally well to Canadiandeposits, is doubtful, though what he says of the origin of theNorwegian deposits might be applied to the Canadian deposits inevery other respect. Those holding to the whole of Vogts opinionexplain the concentration of the ore at or near the contacts in thefollowing way :—Soret proved that if a solution of common salt orother substance be unequally he
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