File:The Quarterly journal of the Geological Society of London (13071204653).jpg

484
PROCEEDINGS OP THE GEOLOGICAL SOCIETY.
I'
be
that the Carboniferous Limestone at this
point formed the wave-washed cliff of the
Liassic sea, and that its caverns were
subsequently filled by Liassic deposits. A
longitudinal section at their junction
would then show similar conditions ; but
we cannot strictly adopt this idea, from
the fact that the same phenomena prevail
throughout the whole line of the Car-
boniferous Limestone, and that the veins
are continued to unascertained depths.
The section now described was as it ap-
peared on the visit of the Members of the
British Association in 1863 ; but every
subsequent working alters its precise fea-
tures, though its general character re-
mains the same.
1. Immediately to the south-east, and
parallel to the Marston road, may be
seen a vertical face of limestone contain-
ing Spirifera Walcottii, S. Munsterii^
Echini, &c., unquestionably of Liassic age.
This appears to be a continuation of the
long face of similar limestone noticed
higher up the road. On entering the
quarry, this limestone is seen to pass
down as a vertical dyke, partly covered
by vegetation on the south, but which
appears to be about 6 feet thick. It is
composed of a wavy, thinly laminated,
yellow or bluish material, occasionally
conglomeratic, and somewhat resembling
marble. It has on its north side
2. A breadth of 10 feet of regularly
bedded Carboniferous Limestone, showing
a considerable inclination to the south,
where it is cut off by the above.
3. A nearly vertical vein, the sides of
which are composed of red, chocolate, or
variegated impure limestone, sometimes
with a central fissure stained with oxide
of iron, or containing ironstone, at others
filled with crystallized carbonate of lime,
9 inches.
4. A thin band of Carboniferous Lime-
stone with organic remains, giving the
appearance of a vertical vein of that lime-
stone, 1 foot 3 inches.
5. Dyke of conglomeratic Lias, passing