Scotland, two different species of
mountains or hills, one composed both in matter and manner exactly
similar to the Alps of Switzerland, the other of whin-stone, basaltic
rock, or subterraneous lava; and as the fossil coal, argillaceous and
sand-stone strata, are found variously connected with those hills,
nothing can tend more to give a proper understanding, with regard to the
construction of the land in general, of the globe than a view of those
different bodies, which are here found much mixed together in a little
space of country, thus exhibiting, as it were in miniature, what may be
found in other parts of the world, upon a larger scale, but not upon any
other principle. I will therefore endeavour to give a short description
of the mineral state of this country with regard to coal, so far as my
experience and memory will serve.

This country might very properly be considered as consisting of primary
and secondary mountains; not as supposing the primary mountains original
and inexplicable in their formation, any more than those of the latest
production, but as considering the one to be later in point of time, or
posterior in the progress of things. The first are those which commonly
form the alpine countries, consisting of various schisti, of quartzy
stone, and granites. The second, again, are the whinstone or basaltic
hills scattered up and down the low country, and evidently posterior to
the strata of that country, which they break, elevate, and displace.

Thus there are in this country, as well as every where else, three
things to be distinguished; first, the alpine or elevated country;
secondly, the flat or low country; and, thirdly, that which has been of
posterior formation to the strata which it traverses, in whatever shape
or quality; whether as a mountain, or only as a vein; whether as a
basaltes, a porphyry, or a granite, or only as a metal, a siliceous
substance, or a spar.

Those three things which are here distinguished do not differ with
regard to the chemical character of their substances; for, in each of
these, every different substance is to be found, more or less; and it
is not in being composed of materials peculiar to itself, that makes an
alpine country be distinguished from a flat country; it is chiefly in
the changes which the strata of the alpine country have been made to
undergo, posterior to their original collection, that the rocks of the
alpine country differ from those of the flat co