If these are mineral operations, proper to the lower regions of the
earth, and exerted upon bodies under immense compression, such things
will be sometimes found in the unerupted lavas, as well as in the
contiguous bodies with which they are associated. If, on the contrary,
these are operations proper to the surface of the earth, where the
dissolving power of water and air take place, and where certain
stalactical and ferruginous concretions are produced by these means;
then, in erupted lavas, we should find mineral concretions, which
concretions should be denied to bodies which had been consolidated at
the bottom of the sea; that is to say, where, without the operation of
subterraneous fire, no changes of that kind could have taken place, as
has already been observed. But in the unerupted species of lava, that
is to say, in our whin-stone, every species of mineral appearance is
occasionally to be found. Let those who have the opportunity to examine,
say, what arc to be found in proper lavas, that is, those of the erupted
kind. Sir William Hamilton informed me, when I showed him those mineral
veins and spars in our whin-stone, that he had never observed the like,
in lavas We have now formed some conclusions with regard to the nature
and production of those parts of the land of this globe which we
have had the means of examining perfectly; but; from the accounts of
travellers, and from, the specimens which are brought to us from distant
parts, we have reason to believe, that all the rest of the earth is
of the same nature with that which has been now considered.
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