Joseph Henry Wade.

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harvests in the Vale of Glamorgan. It is in consequence
a sparsely populated region, and the villages are remote
and little visited except by tourists. Like the rest of the
county the peninsula abounds in antiquities.

5. Geology and Soil.

The geological character of Glamorgan is comparatively
simple. All the rocks have been formed by the action
of water ; there are none of igneous origin. Apart from
the alluvial deposits along the estuaries of the rivers, there
are only five systems represented within the county, the
Silurian, Devonian, Carboniferous, Triassic, and Jurassic.

NAM as or






Pre- Cambrian


Metal Age Deposits

Palaeolithic ,,
Glacial ,,

ICromer Series
Weybourne Crag
Chillesford and Norwich Crags
Red and Walton Crags
Coralline Crag

Absent from Britain

Fluviomarine Beds of Hampshire

Bagshot Beds

London Clay

Oldhaven Beds, Woolwich and Reading

Thanet Sands [Groups


Upper Greensand and Gault

Lower Greensand

Weald Clay

Hastings Sands

Purbeck Beds

Portland Beds

Kimmeridge Clay

Corallian Beds

Oxford Clay and Kellaways Rrx-k


Forest Marble

Great Oolite with Stonesfield Slate

Inferior Oolite

Lias Upper, Middle, and Lower

Keuper Marls
Keuper Sandstone
Upper Bunter Sandstone
Bunter Pebble Beds
Lower Bunter Sandstone

Magnesian Limestone and Sandstone

Marl Slate

Lower Permian Sandstone

Coal Measures
Millstone Grit
Mountain Limestone
Basal Carboniferous Rocks


rj evonian an( j O ld Red Sand-

Lndlow Beds
Wenlock Beds
Llandovery Bed*

Caradoc Beds
l.landeilo Beds
Arenig Beds

Tremadoc Slate*

Lingula Flags

Menevian Beds

Harlech Grits and Llanberis Slate*

No definite classification yet made


Superficial Deposits

Sands chiefly

Clays and Sands chiefly

Chalk at top
Sandstones, Mud and
Clays below

Shales, Sandstones and
Oolitic Limestones

Red Sandstones and
Marls, Gypsum and Salt

Red Sandstones and
Magnesian Limestone

Sandstones, Shales and
Coals at top
Sandstones in middle
Limestone and Shales belou

Red Sandstones,
Shales, Slates and Lime-

Sandstones, Shales and
Thin Limestones

Shales, Slates,
Sandstones and
Thin Limestones

Slates and

Slates and
Volcanic Rocks


But the distribution of these various formations is so
extremely unequal that the list may be virtually reduced
to two the Carboniferous and the Jurassic. Of these
two the Carboniferous so largely predominates that seven-
eighths of the surface of the shire comes under this
classification. It will be seen that the geological map
in its main features roughly follows the geographical
divisions of the county. The whole of the northern high-
lands consists of Coal Measures ; the Vale of Glamorgan
is Lias ; and the peninsula of Gower is Mountain
Limestone. The Silurian, Devonian, and Triassic forma-
tions are only sparsely represented. Their rocks occur
in patches, and form no very striking feature in the
geological field. Taken in the order of their formation,
the various systems will be found distributed over the
following areas :

The Silurian rocks, though occurring in such large
masses elsewhere in South Wales, are only very scantily
exhibited in Glamorganshire. They are found on the
extreme eastern verge of the county and nowhere else.
On the banks of the Rhymney there is a small bed of
shales, sandstones, and mudstones, which projects across
the border from Monmouthshire.

The Old Red Sandstone, which forms the bulk of
the adjoining counties of Breconshire and Monmouth-
shire, continues as far as the river Taff, dips right under
Glamorganshire in a south-westerly direction, and only
reappears within the county as a small outcrop between
Cardiff and Bridgend, and as a range of hills running
across the surface of the peninsula of Gower. The

w. G. 2

f -'


depression caused by the disappearance of the Old Red
Sandstone forms a trough in which the Coal Measures lie.
The Carboniferous system is the prevailing formation
of the county. All the massive hills of the north belong
to it, and the vast area over which it extends is the cause

Sandstone at Fairoak Farm, Roath Park

of the great prosperity of the shire. The coal-bearing
rocks, though lying above the Old Red Sandstone, do not
rest immediately upon it. They are underlaid every-
where by an intermediate bed of Mountain Limestone and
Millstone Grit, which are also classified as Carboniferous

2 2


rocks. Prior to the Carboniferous epoch, the Red Sand-
stone hills of Breconshire formed the shore of some shallow
and clear sea, and Glamorganshire was a submerged ledge
of rock upon which a multitude of coral animals subse-
quently laid down this thick floor of limestone. The
limestone bed not only underlies the whole of the
Glamorgan coalfield, but forms a thick rim round its
southern edge. The deposit varies from 500 to 1000
feet in thickness. The rock is found elsewhere, besides
at the bottom of the coal basin. It occurs immediately
below the Lias in some portions of the Vale, where it
occasionally breaks out on the surface. It forms some
of the most prominent points along the coast, and is
exposed as a long stretch of low rocks between Porthcawl
and Sker Point. It again appears as the predominant
geological feature in the peninsula of Gower, where it
can be seen upheaved at a considerable angle in the bold
cliffs which form the coast. Some of the cliffs in this
district are characteristically perforated with caverns,
which on their first exploration were found thickly strewn
with the bones of extinct animals.

Between the Mountain Limestone and the Coal
Measures is a deposit of Millstone Grit varying from
250 ft. to 1000 ft. in thickness. It comes to the surface
at the foot of the hills stretching as a thin tract of
territory between Caerphilly and Llantrissant. It appears
again as a longish patch north of Bridgend. It is a coarse
quartzose sandstone frequently used for millstones, but
locally known in the coalfield as the " Farewell " rock.
Its general position in Wales is at the base of the Coal


Measures, and the miner who reaches it regards it as a
signal to abandon further search.

The South Wales coalfield stretches from Pontypool
to St Bride's Bay, and has an area of 1000 square miles,
of which Glamorganshire possesses about half. The
extreme length is 90 miles, and the breadth varies from
21 miles in Glamorganshire to i miles in Pembrokeshire.
It rests in a sort of pear-shaped trough with the widest
end towards the east. The greatest depth at which coal
lies is calculated to be about 6650 feet. Across the basin
run two anticlinal folds, one stretching from Risca to
Aberavon, and the other from Cwm Neath to Kidwelly.
Swansea Bay makes a large encroachment upon the
Glamorganshire coalfield, and a colliery near the shore
at Port Talbot is worked beneath the Channel. Though
the Coal Measures have an estimated thickness of 7000 ft.,
the actual seams of coal vary only from I to 6 ft.
thick, and are thinnest and most numerous in the west.
The seams are divided one from another by intervening
masses of sandstone, which in some cases are as much
as 500 ft. thick. The layers of sandstone are again
interspersed with deposits of shale, which measure in
thickness from 10 to 50 feet. Most seams of coal rest
upon a co-extensive cushion of clay, which varies from
6 inches to IO feet in depth. This underclay is in South
Wales, though not elsewhere, an invariable accompani-
ment of the coal, and is believed by some to be the soil
in which the vegetation forming the coal originally grew,
as in some cases it contains rootlets. It is a soft sandy
shale extensively used in the manufacture of fire-bricks.


The absence of soda and potash salts, possibly abstracted
by the plant life which once flourished above it, preserves
it from fusion when exposed to the action of heat.

The coal seams, which lie in three series, are known
as the Upper Coal Measures or Upper Sandstones, the
Pennant Grit, covering most of the coalfield, and the
Lower Coal Measures. In the Upper Coal Measures
the coal is highly bituminous and inflammable, and is
used chiefly for domestic purposes, and for the production
of coal gas and coke. In the Pennant Grit series the
coal is much less plentiful and is sandwiched in between
beds of hard sandstone, which are frequently quarried for
building and paving. This coal readily cakes and is
employed largely in the manufacture of " patent fuel."
The Lower Coal Measures produce the famous steam
coal, so invaluable for boiler furnaces. It contains a
much larger percentage of carbon than the inflammable
varieties, and produces in consequence a much fiercer
heat and less smoke. Glamorganshire supplies virtually
all the larger navies of the world with their fuel. As
the coal seams spread towards the north-west the coal
becomes still less bituminous in character, and to the north
of Swansea in the valleys of the Tawe and Twrch it is
almost purely anthracitic and smokeless.

Though some violent upheaval has lifted the Coal
Measures to their present position as lofty hills, there is
little doubt that they were first laid down at the bottom
of some lagoon into which a number of muddy streams
were constantly discharging a large quantity of earthy
sediment. Rank vegetation sprang up on the more


elevated portions of these swamps, which, owing to their
unstable nature, subsequently sank. The plants which
covered these spongy deposits consisted chiefly of gigantic
mosses and ferns. The forests so formed disappeared
or were renewed as the land fell or rose. The mud
eventually hardened into shales, and the coal seams are
the compressed remnants of these vanished jungles. Some
violent shrinkage of the earth's crust in ages long subse-
quent to its formation raised the coalfield to its present
altitude. The valleys which score the surface of the hills
are not the folds into which the hills were thrown, but
the furrows ploughed out of their surface by the torrents
which coursed down their sides. The streams which
now wind their way at the bottom of the gorges are the
shrunken survivals of these ancient rivers. The Lower
Coal Measures are rich in ironstone and contain a
number of marine shells and Entomostraca. In the Upper
Measures the only fossil foimd, other than the remains of
plant life, is the shell Anthracosia.

The Triassic rocks which occur within the county
are found chiefly as patches of dolomitic conglomerate
near Llandaff, St Fagan's, Coychurch, Pyle, and Newton
Nottage, and are overlaid by Keuper Red Marls in
the neighbourhood of Bridgend. In the conglomerate
of Newton Nottage have been found the footprints of
some gigantic three-toed bird or reptile. A slab from the
district bearing this impression is now exhibited in the
Cardiff Museum. The geological formation of Penarth
Head, where the rocks also belong to this series, is
extremely interesting. At the base of the cliff is a



foundation of red Triassic marls, and upon these reposes
a 28-foot bed of green Rhaetic marls. Above this may
be seen a larger bed of black shales, 24 feet thick, con-
taining a bone-bed rich in the scales and teeth of fishes
and reptiles. This is capped, as the coast trends towards
Lavernock Point, with a deposit of white Lias, 18 feet in

Penarth Cliffs

thickness, and composed of grey and brown sandy shales.
The marls are quarried in the neighbourhood of Llandough
and are ground up for brick-making.

The Lias of Glamorganshire and Monmouthshire is
represented by the Lower Lias only, and borders the
southern part of these counties and the South Wales


coalfield. It occurs more or less in patches, the greatest
development being in the district known as the Vale of
Glamorgan, between Barry and Bridgend, where remark-
ably fine sections can be seen in the cliffs along the seashore.

All along the coast from Lavernock Point to the
mouth of the Ogmore river the Lower Lias shales and
grey limestone rest upon the Rhaetic beds, and con-
stitute the long series of cliffs which form the shore
line of the Vale of Glamorgan. These rocks extend
inwards as far as Cowbridge, and compose the floor of
the Vale. At Southerndown they form a conglomerate
which represents an ancient beach, and may be seen
resting on the upturned edge of the Mountain Limestone.
As may be observed from an inspection of the cliffs the
stratification of the Lias rocks is extremely regular. The
rocks consist of bands of blue limestone six inches in
thickness, between which are interposed layers of shale,
sometimes called, on account of their perfect lamination,
paper shales. The White Lias series contain a large
number of fossils, including shells and the star-fish
Ophiolepsis Damesii. From the Blue Lias rocks have
been obtained more than fifty species of corals, and a
great many Ammonites. Saurian remains are also not
infrequent, Ichthyosaurus and Plesiosaurus being found in
the large quarries attached to the cement works at Penarth.

As one travels westward the thickness of the Lias in-
creases. The total depth in the district round Newport is
only about 30 feet, at Penarth and Lavernock the deposits
attain a thickness of about 130 feet, but in the neighbour-
hood of Aberthaw they reach several hundred feet.

Section of the Lower Lias at Lavernock


Generally speaking, the deposits consist of layers of
blue or blue-grey argillaceous limestone alternating with
blue, white, or yellowish shales and clays, the blue shales
often containing notable quantities of iron pyrites. In the
east the clays and shales predominate and the deposits
attain their most aluminous character ; westward they
become more siliceous and also more calcareous, the beds
of stone greatly predominating.

Surface deposits of alluvial matter occur at the estuaries
of all the rivers and along the valleys of the Nedd and Tawe.
Extensive tracts of marshy land have been formed between
the mouth of the Rhymney and Penarth Head, and at
the foot of the hills in the neighbourhood of Aberavon.
There is a patch of undrained bog at Crymlyn between
the estuaries of the Nedd and Tawe, and some extensive
salt marshes line the southern shores of the Burry Inlet.
The movements of glaciers in the county have left some
traces. The accumulations of sand and gravel which
are found in most of the river valleys, though generally
attributed to excessive rainfalls in prehistoric times, may
really be of glacial origin. There is a glacial drift near
Cardiff consisting of pebbles and boulders of Old Red
Sandstone and other rocks lying immediately to the north.
A number of "erratics" from the local Carboniferous
Limestone and Millstone Grit are scattered about the
Ely valley. But the most interesting deposit is at Pencoed,
where well-polished boulders of rocks foreign to the
district have been found, which microscopic examination
has shown to have been brought from North Wales by
glacial action.


Large boulders of Millstone Grit or Conglomerate
are also frequently met with in Gower.

Iron ore is found in the form of haematite in deposits
amongst the Mountain Limestone, and a great deal of
ironstone is obtainable amongst the lower Coal Measures.
The chief iron-ore district lies in the neighbourhood of
Merthyr, Dowlais, and Aberdare ; and deposits have been
worked near Pentyrch. Gypsum occurs in small beds
near Penarth.

The soil of the different localities varies very con-
siderably both in character and value. In the Vale of
Glamorgan it is a deep rich loam of unusual fertility and
light to handle. It is peculiarly suitable for the production
of wheat. The underlying substratum of limestone adds
considerably to its quality, but gives it a very stony
appearance when turned over. The north, on the other
hand, is a very barren region. The damp peaty earth
with which the mountains are thinly covered is very
poor, and the drier patches are too gravelly to be of any
service to the agriculturist. In Gower again the soil,
though it varies a good deal, as a rule lacks both depth
and virtue. It ranges from a loose red earth to a thick
yellowish clay, and is occasionally interspersed with beds
of sand. In general it yields only a moderate return for
the labour involved in its tillage.


6. Watershed and Rivers.

Glamorganshire is particularly well watered. It
abounds in rivers, though none of them are of any
great size. They are all short, and take their rise either
within the county or else amongst the Brecon hills just
beyond its borders. The watershed lies entirely in the
north, and all the streams run southwards and empty
themselves into the Bristol Channel. They were at
one time distinguished for the picturesqueness of their
surroundings, but their beauty has now disappeared before
the pitiless ravages of industrial progress. None of the
rivers are in themselves of much value as waterways, for
they are narrow, rapid, and shallow. They have neverthe-
less played an important part in the industrial development
of the county, for their valleys are the commercial arteries
of the district, and the estuaries into which they empty
themselves have provided the harbours which now place
the mineral wealth of Glamorgan at the disposal of the
world. The rivers may be conveniently regarded as
falling into three distinct groups, which form the eastern,
western, and central drainage systems of the county.
The easterly basin comprises the Rhymney, TafF, and
Ely rivers, which flow in a south-easterly direction. The
westerly basin consists of the Nedd, Tawe, and Loughor,
which flow south-west. The central basin is drained by
the Ogmore, Kenfig, and Avon, the first two of which
flow southwards, and the last south-west. A subordinate
group of streams, of which the principal constituent is
the Daw, drain the Vale of Glamorgan.


The Rhymney has its birth in Breconshire, but for
the remainder of its career it forms the dividing line
between Monmouthshire and Glamorganshire. Receiv-
ing the Bargoed brook on its way, it follows a fairly
consistent course southwards ; but, before it eventually
reaches the Channel, it has to make an awkward detour
to the east to work round the obstructing ridge of Cefn
Carnau. The valley through which it flows, though
exceptionally rich in minerals, is bare and otherwise
lacking in interest. At Caerphilly, however, there stands
at the entrance of an adjoining vale one of the most
famous of the ruined castles of Wales. Below Caerphilly
the scenery improves until, leaving its gorge, the river
twists itself as a muddy estuary across the flats of Cardiff.

Unlike the solitary Rhymney, the Taff is a veritable
family of rivers. Rising as a twin stream in Breconshire,
it follows a double course as far as the large industrial
town of Merthyr, where the greater Taff and lesser Taff
unite. At Quaker's Yard the river receives a further
accession to its waters in another Bargoed brook, and at
Abercynon its volume is again swollen by the Cynon
river, which likewise descending from the Brecon high-
lands flows, past the large and populous towns of Aberdare
(which stands on one of its feeders) and Mountain Ash.
Another stream falling into the Cynon before it joins the
Taff is the Aman ; and the Clydach, which waters a very
busy little glen, reaches the Taff later. At Pontypridd
the Taff is joined by two other important tributaries, the
Rhondda Fawr and the Rhondda Fach. Both of these
streams have their source in the spurs of Craig-y-Llyn,



and pass through one of the most populous districts in
South Wales. The valleys through which they flow
contain some of the finest steam coal in the world, and
they have in consequence of its discovery undergone a
remarkable transformation. The two Rhondda rivers
coalesce at Forth, and empty their united current into

The Taft

(showing the Garth in the distance)

the Taft at Pontypridd. The position of Pontypridd at
the confluence of these valleys makes it a sort of general
clearing-house for the vast traffic of the district. It
borrows its name from a remarkable one-arched bridge
which a local mason named Edwards built in 1750 across
the TafF. Five miles above Cardiff the Taff emerges from
the mountains and makes its way across the level plain to


the sea. Before the river reaches Cardiff it glides past
the peaceful city of LlandafF, whose rural seclusion
conceals its long and chequered history. The cathedral
is pleasantly situated on the banks of the stream. The
wide tidal estuary by which the TafF finally discharges its
waters into the Channel has given Cardiff the opportunity
of becoming one of the largest ports in the kingdom.

The Ely river is a short stream rising amongst the
hills behind the mining village of Ton-yr-Efail. For a
short distance it wanders amongst the mountains, and then
uniting itself with the Mychedd brook it creeps through a
narrow pass near Llantrissant (Llantrisaint) into the Vale
of Glamorgan. The town of Llantrissant is perched on
a knoll above the river, and its position at the mouth of
the defile made it in medieval times a place of much
strategical importance, and its castle was strongly fortified.
Below Llantrissant the Ely receives the Afon Clun, and
then meanders southwards across the Vale to Peterston,
where there are the remains of another castle. At
Peterston it suddenly turns eastwards, and flowing past
the castle and battle-field of St Fagan's reaches Ely,
where it again bends southwards and finally finds its
way into the estuary of the TafF at Penarth, where it
forms a natural harbour. Some fine docks have been
constructed beneath the headland to supplement the
commercial conveniences of the river.

The rivers of Mid-Glamorgan, like their eastern and
western neighbours, run a short impetuous course amongst
the hills before they seek a more sluggish channel in the
plains on their way to the sea. In number they are


three the Ogmore, the Kenfig, and the Avon. The
Ogmore collects together a number of converging streams
which have their origin amongst the cluster of lofty hills
which are massed together in the centre of the county.
The Ogmore proper, like the Taff, is a combination of
dual streams, the Ogmore Fawr and the Ogmore Fach,
which rise on either side of Carn Fawr (a spur of the
central hills) and unite at Blackmill. At Abergarw the
joint river receives the turbulent waters of the Garw,
which comes rushing down the valley between Mynydd
Llangeinor and Mynydd Caerau. At St Bride's it effects
a junction with a less impetuous but more important
tributary, the Llynfi, which rises on the western side of
Mynydd Caerau, and passes the busy mining centres of
Maesteg and Tondu. Thenceforth the Ogmore flows
a placid stream through the town of Bridgend, below
which it unites with the waters of the Ewenny, and then
empties itself into the Bristol Channel near Button by
an estuary remarkable for its vast accumulations of sand.
The old priory church on the banks of the Ewenny,
and the crumbling ruins of Ogmore Castle near the
estuary, invest it with considerable antiquarian interest.
The Alun brook, which is a tributary of the Ewenny,
cuts its way through a small but singularly picturesque
gorge to join the larger stream, and furnishes the land-
scape with a very striking and unexpected feature. The
Kenfig is little better than a streamlet, and descends from
the steep slopes of Mynydd Margam to push its way to
the sea through the sandy wilderness known as the Kenfig
Burrows. The Avon is a larger river, which rises as a
w. G. 3



mountain brook on the slopes of Crug-yr-Afon, and
joining itself to the Corwg a stream descending from
the lofty spurs of Craig-y-Llyn strikes out a south-
westerly course for Swansea Bay. Before discharging
its waters here at Aberavon it collects two other
tributaries, the Pelena and the Dyffryn. The course
of the river is walled in all the way by bare and rugged

Ogmore Castle

hill sides, and its banks are lined with collieries and

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Online LibraryJoseph Henry WadeGlamorganshire → online text (page 2 of 11)