144 TRANSACTIONS OF THE [marR. 18, 
the theory which I think was first advanced by your worthy 
President, of vein-making due to the aqueous agency in a great 
measure, is without doubt illustrated. 
We go back now to the King’s Mountain gold-mine, and we 
find, at certain depths, changes in the metallic contents of the 
lode or vein,—for what reason I am unable to say, because it might 
appear, by the water action, that the contents of the lode should 
be similar from the surface down, yet we find, as we reach greater 
depths, that a change takes place. Copper appears and there is 
some promise of its occurring in larger quantities; other min- 
erals also are making their appearance. On examining the tin 
formation, we find now and then, along the surface, evidences 
that the slates carry some iron pyrites, but the greisen rock 
shows very little of it near the surface; as depth is reached, how- 
ever, we find cassiterite associated to some extent with iron 
pyrites. This pyrites near the surface appears to be fine, as 
though it had been dusted into the rock and mostly between the 
lamine of the slate; but deeper it assumes a crystalline struc- 
ture and becomes cubical. When again we note the fact that, 
as we go deeper into this tin formation, chalcopyrite also makes its 
appearance, I have come to the following conclusion. It may 
be only an idea ; but as men accustomed to study these matters, 
and to do some little mining, generally form conclusions from 
appearances,—conclusions in some instances not warranted, but 
in other instances proved to be true,—so I have come to believe 
that cassiterite will be found in increasing quantities in depth to 
an extent that will prove it to be of great value, in certain parts 
of the veins. In England, it is a well-known fact that where 
they commenced to mine for copper, deeper work resulted in 
tin, and at greater depths copper again, and at still greater 
depths cassiterite. That would at least tend somewhat to prove 
that there are zones of minerals. And while there is no arbi- 
trary law to prove that tin will occur in greater quantity with 
depth, still, when we consider the fact that it is a crystalline 
mineral, eminently so, I think that as we go deeper, where the 
rock becomes more crystalline, mica-schists grow harder and 
small veins of quartz make their appearance,—bedded veins of 
quartz, two or three inchesin thickness, which do not show on the 
surface and which carry small quantities of cassiterite,—the 
argument to me is in favor of its increasing in quantity as greater 
depth is attained. 
The specimen of greisen on the table is the representative 
rock of the tin formation. I have adopted Mr. Dana’s defini- 
tion of greisen, who calls it a quartzose rock or one belonging to 
the quartz family, because I find it on the one hand graduating 
to the true granite, and on the other hand absolutely to a crystal- 
