GENESIS OF NATIVE COPPER. 459 
■dition of copper oxides, and that by surface erosion the iron gossan, or cap, has 
been removed ; the surface quartz from the leaching out of the sulphides is honey- 
combed, loose and friable. Now let a geological change come, by which in the 
subsidence of a large area of dry land, our copper deposit is submerged many 
thousand feet under an ocean. 
The weight or pressure of all this water, would act in making our formation 
more compact. If we could see it then, we would find a vein, or mineral bearing 
quartz, iron and copper stained, amongst the top layers, packed firmly together, 
but if taken from under this pressure of water, easily disintegrating; and further 
down in the gangue we would keep getting a greater proportionate showing of 
copper, owing to the previous leaching action already described, but it will not 
do to take our deposit out just yet. 
Let us go outside in our reasoning a little ; all of the large masses of eruptive 
Tock known, except lava of recent date and pumice stone, have been thrust up, in 
the form of volcanic pastes, through the earth crust, or floor under an ocean. Now 
if such were to happen, in near proximity to our copper oxide deposit, the result 
would be, from the heat and pressure of such an occurrence, that all of our oxides 
would gradually change to native, or metallic copper. I reason, gradually, as 
the pressure and presence of such an enormous mass of water would prevent the 
■copper melting as in a furnace. It would produce such changes as would be 
best described by the word metamorphism. The quartz also would be metamor- 
phosed into a very much harder form and be more homogeneous in texture, but with 
scales of native copper all through, these of course increasing in quantity as depth 
in the formation is gained. 
If this quartz had cavities in it before the submergence, which could have 
been filled with the copper oxides during the leaching period, then there would 
be found in places large masses of native copper, and which are found in Lake 
Superior regions, the result or product of just such a natural process as I have 
described. 
There, as is well known, we have trachytes, basalts, and porphyries in vast 
amounts, and it is owing to these being erupted under the conditions described, 
and in near proximity to what had been, in the past, a duplicate of the Arizona 
copper formations, that we have the pure form of metallic copper as a natural 
-occurrence upon the shores of Lake Superior. 
Now, if ever a duplicate of the formation of this region is found it will also 
be found that surrounding it, perhaps also on top, (the result of a flow of volcanic 
paste) will be found some of the varieties, and in very large quantity too, of 
eruptive rocks; if so, then the copper product will duplicate that of the Lake Su- 
perior mines in quality, with perhaps this chance for variation in quantity. That 
perhaps the quartz did not contain cavities to allow of the accumulation of large 
masses of copper oxides, hence there will be no large masses of native copper, 
but the metal will be evenly distributed throughout the whole of the quartz, not 
•varying much in quantity in planes of the same horizon, but rapidly increasing 
throughout the whole of the mass as depth is gained in the formation. 
