SALMON— ON THE li-OBMATION OF ORR-VEIN.S. 
365 
At Hntte, two leagues from Freiberg, on the edge of the Tha- 
rander porpliyry-mass, and in an isolated stock-form mass, galena, 
blende, and pyrites likewise occur in drusy vesicles of the porphyry, 
and gold is even said (although not on entirely reliable authority) to 
be found in the pyrites. But what are particularly and indisputably 
important for our considerations are the ore-holding felsite-rock or 
porphyries in the neighboui-hood of Braimsdorf, near Freiberg, 
which H. Miiller has investigated and especially described in this 
volume. 
Now is it not, at all events, a very remarkable circumstance that 
in the eruptive porphyry-formations of the environs of Freiberg the 
same ores and minerals occm* disseminated which entirely prevail in 
the ore-veins of the same neighbourhood ? Certainly, these ore- 
veins are in general of more recent origin than the porphyi'ies, 
which they almost everywhere penetrate. But H. Miiller has shown 
that, at the Reinsberger Gliick Mgg. of Emanuel ErbstoUn, the oldest 
Freiberger ore-veins, those of the great quartz-formation, are also 
penetrated and disturbed by certain porphyries, and that consequently 
both formations— ore-veins and porphyries — belong to one epoch, 
in the sense that the fiUing-up of the ore-veins in general is to be 
considered as a consequence of the porphyry-eruptions. 
A new set of statements or a novel experience can never be sup- 
ported by too many facts. I shall therefore here again cite that the 
dolomitic limestone, which at Tharander lies in the oldest clay-slate, 
sometimes contains, exactly at the point where it is disturbed by the 
porphjTy, crystals of pyrites, copper-pyrites, galena, blende, and 
baryte, in drusy vesicles. May we not suppose that the occuiTcnce 
of these minerals here is conditional upon the contiguity of the por- 
phyry, as in the Freiberger ore-veins ? 
As volcanic activity on the land or at the bottom of the sea really 
by no means consists merely in the pressing-up of lava, but is most 
intimately connected with great earthquakes — the opening of 
fissui'es, the exhalations of gas and vapours, and the production of 
hot and mineral springs — so it is also certain that the pressing-up of 
the older massive rocks was combined with like complicated events. 
And if, in those earlier periods of geological time, we are entitled to 
assume the existence of a thick heavy atmosphere, and, as a con- 
VOL. II. G G 
