352 R. Pumpelly—Paragenesis of Copper 
in the various suphurets, or as oxidation products of these. 
Indeed we cannot well suppose the copper to have been deposit- 
ed in submarine formations in any other condition than as 
sulphuret. Nor can we suppose it to have taken any other form 
permanently, so long as unoxidized organic matter remain 
s. An oxidation of the sulphuret would be followed 
by reduction of the resulting sulphate to new sulphurets 
around the organic remains. In this way we may suppose the 
simplest and most common form of concentrated deposits 
_ —the impregnations—to have originated, as well as the farther 
enrichment of particular beds or zones—fahlbands—which may 
represent strata which were originally richer in organi¢e sub- 
— or which may have retained these longer than the other 
s. 
e 
But the general diffusion of copper through the varied rocks 
of the Quebec group, speaks for a marine origin for the metal 
in these traps. It should seem probable that the copper the 
melaphyrs was derived by concentration from the whole thick- 
ual processes 
association of sulphur with copper in crystalline rocks, rende 
it See probable that this was here also the combination ™ 
which the ially C00 
trated. Traces of sulphur detected by Mr. Hochstetter 
