The _third_ reason for supposing those mountains primitive, is taken
from the metallic veins, which are found so plentifully in these masses.
Now, had these masses been the only bodies in this earth in which those
mineral veins were found, there might be some species of reason for
drawing the conclusion, which is here formed by our philosopher. But
nothing is so common (at least in England) as mineral veins in the
strata of the latest formation, and in those which are principally
formed of marine productions; consequently so far from serving the
purpose for which this argument was employed, the mineral veins in the
primitive mountains tend to destroy their originality, by assimilating
them in some respect with every other mass of strata or mountain upon
the globe.
_Lastly_, M. Pallas here employs an argument taken from an appearance
for which we are particularly indebted to him, and by which the
arguments which have been already employed in denying the originality
of granite is abundantly confirmed. It has been already alleged, that
granite, porphyry, and whinstone, or trap, graduate into each other; but
here M.
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