racture and dislocation is the
principle; but there is no other principle upon which strata, or masses
formed at the bottom of the sea, can be placed at a height above its
surface. Hence, in those two different operations, of forming mineral
veins, and erecting strata from a lower to a higher place, the principle
is the same; for, neither can be done without violent fracture and
dislocation.

We now only want to know, how far it is by the same power, as well as
upon the same principle, that these two operations have been made.
An expansive force, acting from below, is the power most proper for
erecting masses; but whether it is a power of the same nature with that
which has been employed in forming mineral veins, will best appear in
knowing the nature of their contents. These, therefore, may be now
considered.

Every species of fracture, and every degree of dislocation and
contortion, may be perceived in the form of mineral veins; and there is
no other general principle to be observed in examining their form. But,
in examining their contents, some other principle may appear, so far as,
to the dislocating power or force, there may be superadded matter, by
which something in relation to the nature of the power may be known.
If, for example, a tree or a rock shall be found simply split asunder,
although there be no doubt with regard to some power having been applied
in order to produce the effect, yet we are left merely to conjecture at
the power. But when wedges of wood or iron, or frozen water, should be
found lodged in the cleft, we might be enabled, from this appearance, to
form a certain judgment with regard to the nature of the power which
had been applied. This is the case with mineral veins. We find them
containing matter, which indicates a cause; and every information in
this case is interesting to the theory.

The substances contained in mineral veins are precisely the same with
those which, in the former section, we have considered as being made
instrumental in the consolidation of strata; and they are found mixed
and concreted in every manner possible.

But, besides this evidence for the exertion of extreme heat, in that
process by which those veins were filled, there is another important
observation to be gathered from the inspection of this subject. There
appears to have been a great mechanical power employed in the filling of
these veins, as well as that necessarily required in making the first
fracture