266 Lead Mines, &c. of Hampshire County, Mass: 
nians would say, tliat they were once fissures, and were filled 
from above with a mineral solution, that once covered the 
globe ; and if the question were asked, how these fissures 
were made, they would say that the mountains were unequal- 
ly supported, and one part subsided, thereby forming a fissure ; 
and also that fissures were sometimes made by desiccation of 
the rocks. Against these suppositions the following conside- 
rations may be stated. 
If desiccation, or subsidence of the mountain, produced 
- these fissures, they would be widest on the surface, and nar- 
rower as they descend into the rock; but the reverse is the 
fact. These veins have been invariably found, when wrought, 
to be narrowest on the surface, but to widen as the shaft went 
down into them. nd again, if a mineral solution did once 
cover the globe, we ought, by the laws of gravitation, to 
find beds of metallic matter in vallies and plains; but no 
such beds are found in this region, and no one will suppose 
that there was just enough of this mineral solution to fill the 
fissures, and no more. But, granting that this was actually 
h se, I cannot conceive by what law this mineral solution 
would direct itself to the fissures only, when their surfaces 
were so insignificant, and when the fissures were much high- 
er than vallies or plains. It is only in elevated regions, that 
the galena veins of this neighborhood are seen, and the sup- 
position that they were filled from above, is at war with un- 
doubted philosophical principles. Nor do I believe with the 
Plutonians, that these veins were filled by an injection from 4 
fiery furnace below, but that they are cotemporaneous wi 
the rocks in which they are found; and I think that I am 
warranted to make this conclusion from the following facts. 
_ Ist. They are perfectly analogous to granite veins foun 
in this region. It will be said, that the walls of metallic 
veins correspond to.one another. It is true ; and such 438 
the fact with the granite veins found in this region ; and 
in one instance I saw a granite vein traversing mica slate, 
and passing directly through a nest of quartz, leaving one 
half of it on one side, and the corresponding half on the 
other; but the vein of granite was firmly adhering to the 
quartz and mica, without the least fissure between them. That 
‘ametallic vein does not adhere to the walls so firmly, is 9° 
ent against its cotemporaneons origin with the rock in 
itis situated. In one case the vein is lapideous, in the 
itis metallic; they arediflerent. == 
Pie 
Wi 
