That is to say, the whole of this included space, both sea and
land, has been invaded from below with melted masses of whin-stone,
breaking up through the natural strata of the country, and variously
embossing the surface of the earth at present, when all the softer
materials, with which those subterranean lavas had been covered, are
washed away or removed from those summits of the country. Hence there is
scarcely a considerable tubercle, with which this country also abounds,
that may not be found containing a mass of whin-stone as a nucleus.
But besides those insulated masses of whinstone that form a gradation
from a mountain to a single rock, such, for example, as that on which
the Castle of Edinburgh is built, we find immense quantities of the same
basaltic rock interjected among the natural strata, always breaking and
disordering them, but often apparently following their directions for a
considerable space with some regularity. We also find dykes of the same
substance bisecting the strata like perpendicular veins of rock; and, in
some places, we see the connection of these rocks of the same substance,
which thus appear to be placed in such a different form in relation to
the strata.
Pages:
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558