tion; and the confequent importance of
acquiring mineraiogical knowledge.: He
fhews that many manufactures of the great-
eft confequence depend entirely on mineralogy,
and in page xxiii. begins a confutation
of the Huttonian fyftem, which continues
to the end of the preface, p. lxii.
A chief end of this analyfis, is to feleCt
the real faCts and obfervations, which in
this work, are buried in a mafs of idle
declamation. Such is that, p. xlix. that the
rich vein of lead at Llangunog in Montgo-
meryfhire; which was five yards wide of
folid ore, was found fuddenly cut off by
a deep bed of fhiftus. This preface concludes
with a prayer, the author being a
very good chriftian.
P A R T L
7 he Jlrata o f Coal and its Attendants.1
T h e author fir ft inveftigates the regularity
and inclination of coal ftrata. The
incumbent fubftance is called the roof, while
that below the coal is termed the pavement,
which generally proceeds in a manner fur-
prifingly regular, except when interrupted
by troubles. Thefe confift of flips, dykes,
gafhes, and other circumftances. The moft
common is the flip of the Englifh colliers,
the dyke of the Scotifh, in which the ftrata
are broken afunder, and thrown up or down
on the other fide of the flip. Parallel flips
N 2 cut