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It is not well known what place some of these granites, sienites,
and porphyries hold in the series of rocks: from the scarcity of
places at which their junction with the slate rock can be seen,
it is not easy to ascertain whether they have been deposited upon
that substance or protruded through it: but the latter seems the
more probable supposition.
The greatest bulk of these mountain rocks have been commonly
included under the general appellation of slate; although many of
them shew no disposition to the slaty cleavage. They may be
classed in three principal divisions.
Of these divisions, the FIRST or lowest in the series, forms
Skiddaw, Saddleback, Grasmoor, and Grisedale Pike, with the
mountains of Thornthwaite and Newlands; it extends across
Crummock Lake, and by the foot of Ennerdale as far as Dent Hill;
and after being lost for several miles, it is elevated again at
Black Combe.
If we regard the granite of Skiddaw as a nucleus upon which these
rocks are deposited in mantle-shaped strata, that which reposes
immediately upon it is commonly called gneiss; but it is rather
more slaty and less granular than the gneiss of some other
countries. More distant from the granite, the quantity of mica in
slate decreases, and it is marked with darker coloured spots; it
is then provincially called whintin, and is quarried for
flooring-flags and
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