this ftratum appears uppermoft, but as it
has the general eharader before defcribed,
it will be unneceffary.
The furface where the ftratum of fhale
or fhiftus makes its appearance is next in
fucceflion. It moft frequently appears uppermoft
in vallies formed by limeftone
mountains on one fide, and grit ftone on the
other, where it is generally covered with
loofe irregular pieces of ftoney matter, called,
ratchell, which has probably fallen from the
adjoining mountains in the lapfe of ages.
Shale is fubjed to decompofe by the adion
of the atmofphere, and where it is expofed, it
falls into a black earthy matter; it is not con-
fidered as a fubftance friendly to vegetation,
though when immediately in contad with
limeftone, its properties appear altered. In
many places it is much impregnated with
vitriol and martial pyrites. Lime ads very
powerfully on it, and in many vallies it is
well covered with vegetable earth, and
forms good land.
The form and general appearance of
limeftone mountains next prefent them-
felves to view. In many parts they are
perpendicular and overhanging, prefenting
bare rocks in a great variety of forms, with
diftind marks, ftratification, openings, or
caverns, of which none of the preceding
ftiew any eharader.
The appearances of diflocation and fepa-
ration in thefe mountains, are evident marks
of the violent efforts of nature. Limeftone
in the north and weft, in this county, generally
forms large trads of mountains, ri-
ftng to a conftderable height from the valley
to the fummit; they then range more regularly
to their furtheft extent.
The lime generally ufed in the fouth of
Derbyshire, k brought from Breedon, on
14 tire