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The direction and inclination of the strata are more
distinguished by stripes and alternations in the colour and
texture, than by any natural partings or strata seams; and the
slates are split of various thickness, according to their
fineness of grain, and the discretion and skill of the workman,
without any previous indication of the place where they may be so
divided. They do not separate into thin flakes, like those of the
former division; but some of them, when long used, are subject to
a peculiar species of decay, which operates most powerfully on
parts least exposed to the weather.
Most of the rocks of this division effervesce in some degree with
acids, but more especially those possessing the slaty structure.
They are not very productive of metallic ores, although they
afford a considerable variety. Lead ore has been got in
Patterdale; copper at Dalehead in Newlands, which is near the
northern boundary of the division - it consists of grey and
purple copper, with specimens of malachite. A mine at Coniston,
near the southern boundary, produces the yellow sulphuret; and a
vein of the same was a few years ago opened at Wythburn. Small
veins of iron ore are frequently met with, but scarcely thought
worth notice. The famous plumbago or black-lead mine of
Borrowdale is also situated in this division: but no organic
remains have been discovered in either this or the preceding.
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