Lewis Topographical Dictionary - OSi Online Shop

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mountains on the north, east, and south. Brisselstown
hill, and its lateral extension to the west, called Spynan’s
hill, consist of mica slate, fine and minute granular
greenstone, and greenstone porphyry: the mica slate
in the western part is porphyritic, containing numerous
crystals of felspar; and similar translations, as also into
greenstone porphyry by an intimate intermixture of
hornblende, are observed in various surrounding locali-
ties. Garnet, in general so constant a companion of
mica slate, is seldom seen in the strata of this county,
but hollow spar occurs in some places. The low range
of hills west of Blessington, and the rest of the north-
western border of the county, are based on clay-slate.
On the eastern side of the county, between the mica
slate range and the sea, the prevailing rock is clay-
slate, but in detached situations are found granite ris-
ing from beneath it, and quartz and trap rocks asso-
ciated with it. The granite of this tract is very re-
markable, as seldom comprising quartz; the chief ingre-
dients being simply felspar and mica, forming in one
part pure felspar porphyry. The central and south-
eastern parts of Dunganstown hill are composed of
greenstone; but the prevailing rocks to the south are
clay-slate and quartz, extending down the Avonmore
and Ovoca, and the varieties which they display are
very numerous. The varieties of clay-slate, which are
here all quartzose, abound in contemporaneous veins of
pure quartz, which are more or less metalliferous: the
western extremity and the brow of Croghan Kinshela
mountain consist of granite, with broad veins of quartz
towards the east, succeeded by alternations of granite
and clay-slate, terminating in interstratifications of clay-
slate and greenstone, beyond which is found only the
clay-slate, traversed by veins of quartz, sometimes
metalliferous. Beds of granular felspar in the prevail-
ing clay-slate are worked for building on the right bank
of the Avonmore, north-west of Rathdrum. Bordering
on the Derry or Aughrim river, and likewise near the
Ovoca, in its course from Newbridge, are numerous
beds of greenstone. Arklow rocks, on the coast, south
of the mouth of the Ovoca, present ill-defined columns
of greenstone, with four, five, or six sides: the north-
ern part of the hill consists in general of greenstone:
on the north-western side is a variety of the character
of basalt. Quartz rock forms a prominent naked ridge
on Coollattin hill, in Shillelagh, and constitutes also a
very extensive mountain range from the banks of the
Avonmore above Rathdrum to those of the Vartrey,
comprising the high naked ridge of Carrickmacreilly
and the picturesque rock of Cronroe. In the northern
extremity of the county it forms the Great and Little
Sugar-loaf, Bray Head, and a great part of the neigh-
bouring hills. In no part of the county have organic
remains been found in its rocks. It is also remarkable
that there is a total absence of metallic ores on the
western side of the great granitic mass, while on the
eastern they are found in abundance. A vein of lead
has been worked and apparently exhausted in the
granite brow of Carrigeenduff, on the banks of Lough
Dan; another, called the Luganure vein, wholly in
granite, intersects the mountain of Comaderry, and is
now very productive. Another great vein which has
been worked crosses the upper part of Glendalough;
and in the alternating beds of granite and mica slate
on the northern side of Glenmalur is the great vein on
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which are the lead mines of Ballinafinchogue, and which
comprises, besides, galena, white lead ore, blende, and
copper pyrites. The above minerals are found at all
these places, in true veins; but in the only other me-
talliferous tract, situated in the clay-slate district, they
are found only in beds, in contemporaneous veins, or
in alluvial deposits. This tract is about ten miles in
length, from Croghan Kinshela, across the northern end
of the vale of Ovoca, towards Rathdrum. Its most
celebrated produce has been the alluvial gold, found in
the gravelly deposits of the streams descending from
the eastern side of Croghan Kinshela, and discovered
in 1796: of this a further notice will be found under
the head of Arklow, in the union of which place it is
included. As no trace of auriferous veins could be found
in the mountain by the most persevering efforts, the
works necessarily ceased when the stream ore was ex-
hausted. Trials were also made in Croghan Moira
mountain, but without effect. Metallic substances,
however, are diffused through the whole district in dis-
seminated particles, in slight layers, in contemporaneous
veins and strings, and in massy beds, which latter are
principally composed of copper pyrites and iron pyrites.
The rocks have been perforated in various directions
by the works of the associated Irish Mine Company,
the line of which, extending into Connery and Tigrony
hills, occupies more than one thousand fathoms. These
are on the north side of the Ovoca, and there are other
productive works on the opposite side, especially in
Ballymurtagh. In Kilcashel some trials have been made,
and copper-ore has been met with; and indications of
copper in Avondale, and of lead in Knockanode, have
also been found in the form of slight strings. The
abundance of building stone in every part of the county
appears from the previous detail: the granite used in the
building of the Bank of Ireland, the library of Trinity
College, Nelson’s Pillar, and several other of the pub-
lic buildings of Dublin, was raised from the Golden
quarry near Blessington, but the clay-slate is seldom
found in layers sufficiently thin for roofing; there are,
however, good slate quarries in the parishes of Carnew
and Dunganstown.
The flannel and frieze manufactures were formerly
of considerable extent, the chief market for their pro-
duce being Rathdrum, where a handsome flannel-hall
was erected by the late Earl Fitzwilliam, but they have
entirely declined, and their only vestige is the manufac-
ture of a little frieze for domestic use. The principal
fishery is that of herrings at Arklow, which, however,
has much declined. They are also taken by a few
fishermen at different places along the coast, but the
extension of this branch of industry is checked by the
want of safe harbours for the boats. Oysters are also
taken at Arklow, and carried to Liverpool and Dublin.
The trade of the county consists chiefly in the exporta-
tion of its agricultural and mineral produce, and in the
importation of the various supplies of foreign articles
and manufactured goods necessary for its inhabitants.
Although Dublin is a principal market for the northern
part of the county, Wicklow is a very improving port,
where there are several stores; and grain and cattle are
sent from the southern part of the county to New Ross.
This branch of the trade is entirely carried on by
ordinary land carriage, as the county is devoid of river
or canal navigation, or rail-road communication.