152 Analysis of Scientific Books. 
sionally visited by the metalliferous veins of the strata under- 
neath. Various bituminous substances also are found in it, 
and abundance of vegetable impressions, together with some 
marine shells. Considered ina general point of view, this 
serics is intermediate in character and composition, as it is in 
position, between the main coal measures which it supports, and 
the mountain lime which it covers, forming the natural link 
between them. 
This whole series reposes upon an important assemblage of 
strata, chiefly calcareous, which our authors, from its association 
with coal, call carboniferous limestone ; as it forms considerable 
hills, and is rich in metals, the terms mountain and metallifer- 
ous limestone have also been applied to it. Its prevailing 
colour is gray, and itis generally hard enough to take a good 
polish; it is often magnesian, ferruginous, and bituminous ; 
its various strata being divided either by partings of clay, grit, 
or shale, or by alternations of that variety of trap rock, called 
in Derbyshire ¢oadstone. It contains nodules of chert, arranged 
something like the flint in chalk, and it is remarkable for the 
prevalence of empty fissures and caverns; rivers which flow 
across it are often ingulphed, and pursue for a considerable 
distance a subterranecous course; it abounds in rocky dales 
and mural precipices, and forms much of the most picturesque 
and romantic scenery of England. Itis, moreover, the principal 
depository of the British lead mines, those of Northumberland, 
Durham, Yorkshire, Derbyshire, and Cumberland, being all 
situated in it; it also affords ores of some other metals, anda 
variety of beautiful crystallized minerals. The organic remains 
of this limestone differ from those of the superincumbent strata, 
but resemble those of the inferior limestone, which our authors, 
following the nomenclature of the Wernerian school, call ¢ran- 
sition limestone, but which we can see no sufficient reason for 
considering as a distinct formation, This, however, as well as 
some other points upon which we feel inclined to differ with 
Messrs. Conybeare and Phillips, we shall take occasion to 
advert to in our notice of their second volume. Vertebral 
remains, though rare, are found here; there are also many 
species of testacea; zoophytes, and especially encrinites and 
corallites, are profusely abundant ; and indeed the whole mass 
of rock sometimes seems as if entirely made up of them, whence 
it has been called encrinal limestone. The strata of carboni- 
ferous limestone exhibit all the irregularities of the accompany- 
ing coal measures ; they are often greatly inclined, contorted, 
and dislocated; and, when they alternate with argillaceous 
strata, they generally abound in springs, which break out often 
with singular impetuosity. The hot springs of Buxton, Mat- 
lock, and Clifton, are upon this formation; the waters are 
generally remarkably pure and pellucid, though sometimes so 
