the upper valley of the Towy, is exceedingly
beautiful and varied. On its eastern borders adjoining Breconshire rises
the imposing range of the Black Mountains (_Mynydd Du_), sometimes
called the Carmarthenshire Beacons, where the Carmarthen Van attains an
elevation of 2632 ft. Mynydd Mallaen in the wild districts of the
north-east corner of the county is 1430 ft. in height, but otherwise few
of the numberless rounded hills with which Carmarthenshire is thickly
studded exceed 1000 ft. The principal river is the Towy (_Tywi_), which,
with its chief tributaries, the Gwili, the Cothi and the Sawdde, drains
the central part of the county and enters the Bay at Llanstephan, 9 m.
below Carmarthen. Coracles are frequently to be observed on this river,
as well as on the Teifi, which separates Carmarthenshire from
Cardiganshire on the north. Other streams are the Taf, which flows
through the south-western portion of the county and reaches the sea at
Laugharne; the Gwendraeth, with its mouth at Kidwelly; and the Loughor,
or Llwchwr, which rises in the Black Mountains and forms for several
miles the boundary between the counties of Carmarthen and Glamorgan
until it falls into Carmarthen Bay at Loughor. All these rivers contain
salmon, sewin (_gleisiad_) and trout in fair numbers, and are
consequently frequented by anglers. With the exception of the Van Pool
in the Black Mountains the lakes of the county are inconsiderable in
size.

_Geology._--The oldest rocks in Carmarthenshire come to the surface in
the Vale of Towy at Llanarthney and near Carmarthen; they consist of
black shales of Tremadoc (Cambrian) age, and are succeeded by
conglomerates, sandstones and shales, with beds of volcanic ash and
lava, of Arenig (Ordovician) age, which have been brought up along a
belt of intense folding and faulting which follows the Towy from
Llangadock to Carmarthen and extends westwards to the edge of the
county at Whitland. The Llandeilo shales, flags and limestones and
occasional volcanic ashes, which follow, are well developed at
Llangadock and Llandeilo and near Carmarthen, and are famed for their
trilobites, _Asaphus tyrannus_ and _Ogygia Buchi._ Shales and
mudstones and impersistent limestones of Bala age come next in order,
and, bounding the Vale of Towy on the north, extend as a narrow belt
north-westwards towards the Presley hills. Except for the foregoing
deposits the great area between the Teifi and the