364 
THE GEOLOCilST. 
compact tin-holding ore-veins (like those at Ehrenfriedersdorf in 
Saxony) in and near the stock-formed masses. 
"We here see four or five modes of vein-filling in connection with 
one principal event — the eruption of a crystallized massive rock : 
they are, crystallization out of the yet soft neighbouring rock, sub- 
limation, infiltration, alteration, and injection in a hot fluid con- 
dition ; and many of these modes of filling up are found combined 
in one rock-fissure. 
Similarly situated to these tin-containing granites are the ore- 
containing gTcenstones in the neighbourhood of Schwarzenberg in 
Saxony, only the latter are mostly pressed into narrow parallel 
fissures in the slate, and are therefore, although not more important, 
much richer in metal than the former. I think I have already, in 
1833, sufficiently proved their injective origin.* In them also the 
sublimation-, infiltration-, and alteration-products are added to the 
original injected vein. When we find, in the same neighbourhood, 
greenstone-veins as free from ore as the others are rich in it, we 
must remember that the circumstances of the injection and cooling 
may have been extremely different. 
It is a distinguishing feature of all these plutonic injective and 
secretion veins that their mineral species (which they contain) are 
never carbonates, fluor-spar, or baryte, but hornblende, augite, 
garnet, quartz, mica, and felspar, and such other minerals as usually 
occur as constituents of massive rocks. 
The porphyry-veins also, in the environs of Freiberg, contain 
manifold ores. In the vein which passes near the Muldener Hiitte, 
pyrites is found thickly sprinkled ; and in a new quarry opposite 
this same Hiitte there are a number of druses and vein-like cavities 
in the porphyry, covered with coatings of pyrites, galena, blende, 
calcspar, and baryte. These same minerals occur here not only in 
lenticular clefts and fissures, but also entirely enclosed as small nests 
in the porphyry, to which they evidently most intimately belong. 
Similarly, the porphyry-veins of the Nonnen- and Fursten-waldes at 
Kl. Waltersdorf are interpenetrated with many ore-holding quartz- 
branches. 
* Erliuitcningen zur Gcogn., Karte von Sachson, Tli. II, S. 217 — 2'lfi. 
