: This has a reference to very curious observations which we
made upon the east coast where these mountains terminate, and which I am
to describe in the course of this work.]

"Among the masses of limestone lately broken off for use, and having the
fractures fresh, I found the forms of cockles quite distinct; and in
great abundance.--I send you three pieces of this kind," etc.

It may perhaps be alleged that those mountains of Cumberland and
Tweedale are not the primary mountains, but composed of the secondary
schistus, which is every where known to contain those objects belonging
to a former earth. Naturalists who have not the opportunity of
convincing themselves by their proper examination, must judge with
regard to that geological fact by the description of others. Now it is
most fortunate for natural history, that it has been in this range of
mountains that we have discovered those marks of a marine origin; for,
I shall afterwards have occasion to give the clearest light into this
subject, from observations made in other parts of those same mountains
of schist, by which it will be proved that they are the primary
strata; and thus no manner of doubt will then remain in the minds
of naturalists, who might otherwise suspect that we were deceiving
ourselves, by mistaking the secondary for the primitive schistus.

I have only farther to observe, that those schisti mountains of Wales,
of Cumberland, and of the south alpine part of Scotland, where these
marine objects have been found, consist, of that species of stone which
in some places makes the most admirable slate for covering houses; and,
in other parts, it breaks into blocks that so much resemble wood in
appearance, that, without narrow inspection, it might pass for petrified
wood.

We are therefore to conclude that the marks of organised bodies in those
primary mountains are certainly found; at the same time the general
observation of naturalists has some foundation, so far as the marks of
organised bodies are both rarely to be met with in those masses, and not
easily distinguished as such when they are found.

But this scarcity of marine objects is not confined to those primary
mountains, as they are called; for among the most horizontal strata, or
those of the latest production, there are many in which, it is commonly
thought, no marine calcareous objects are to be found; and this is a
subject that deserves to be more particularly considered, as the theory
m