KILKENNY GEOLOGY

As the soil is seldom much raised above the rock that forms its basis, it is not difficult to trace the substrata: these are granite, silicious schistus, silicious breccia, argillite, sandstone and limestone. The granite hills form a very small part of the county, being merely the extension of the Wicklow group, which, including Mount Leinster and Blackstairs in the county of Carlow, forms the hills of Brandon between the Barrow and the Nore, and ultimately terminates in the low and secondary hills which unite to the south, towards the mountains of Waterford. The stratum which usually joins the granite is silicious schistus, and lower down argillaceous slate. The granite varies in shades of grey, red, and yellow, and in the fineness of its grain; the best is of a light yellow tint, finely grained and corn-pact; black mica is found in it, together with specks of iron ore and crystals of schorl: it can be raised in blocks of large size, and may be chiselled into any form. Below Innistiogue, part of the hills are composed of granite; on their lower part the yellow mica is sometimes found by itself in large masses. The detached stones which form the surface of these hills are called fire-stones, and are worked into hearth-stones, and also applied to other purposes. Pieces of a very fine deep red and compact jasper, of various sizes, the largest ten or twelve inches long and half as broad, have been discovered in the granite district. The silicious schistus is blackish, sometimes containing grains of quartz; when broken it has a shivery texture and thin lamellae, and is hard enough to scratch glass.

The base of Brandon Hill, and of that extending thence to Graig, is composed of it; between Innistiogue and Ross it is quarried out of the steep banks of the river. New Ross is mostly built of it: the dip of these quarries is eastward. Martial pyrites frequently lies between the beds of this stone: the strata are also intersected by broad veins of quartz: iron ochre occurs in it, and it is much tinged by oxyde of iron. A few specks of copper are sometimes perceived, but no vein has been discovered. Fine-grained galena has also been detected in it, in small quantities and in detached fragments. Silicious breccia forms many of the lower hills: it consists principally of fine quartz sand, united by a silicious cement and enveloping rounded pebbles of quartz, from the size of a pea to two or three inches in diameter, and of a reddish tinge: it seems to be one of the stones styled by Kirwan semiprotolites, and wherever its base can be discovered, it appears to lie on silicious schistus. This stone is constantly accompanied by red argillite, which covers the sides of the hills, but scarcely ever the summits: it prevails on the northern sides of these hills, and from its appearance is sometimes called red slate. The hills of breccia run southward from the Nore, spreading to the south and south-east till they approach the Suir: the great hill of Drumdowney, bounded by the Ross river, forms the extremity of the principal range. The stone here is of a fine grain, and is raised for mill-stones, which are principally quarried on the top of the hill of Drumdowney, where an enclosure of about 300 acres has been made for the purpose: they are sent coastwise to Cork, Dublin, and other ports; the dimensions of the largest are five feet in diameter and sixteen inches in the eye.

This stone is sometimes accompanied by a fine-grained white sandstone, consisting chiefly of quartz with a silicious cement: its chief defect is that the strata are very thin. Slaty argillite also often forms the lower parts of those hills, varying from reddish brown to green or blue, but being very heavy is not well adapted for roofing. In the western part of the county there is an extensive quarry of excellent slates, scarcely exceeded by any in colour and lightness. The northern part, including the whole of Fassadineen and the upper part of Gowran, consists either of ferruginous argillite, or of silicious schistus: of the latter, stones are raised in several quarries for the purpose of flagging; the former is always found above the coal, and is thence called coal-cover. It is a brittle blackish slate impregnated with iron ochre, and more or less inlaid with nodules of iron ore; it extends from the collieries to the south and west, forming the banks of the Dinan almost to its confluence with the Nore. The same stone forms lower hills which stretch towards the river, but in that part it is generally found of a fine soft grain, some of which is quarried for polishing marble, and the finer specimens are sometimes used as hones. In several parts are numerous escars, mostly near the banks of the rivers; some are seen near Urlingford, approaching the verge of the Bog of Allen, and they are also frequently found far removed from either river or bog; they are mostly composed of rounded masses of limestone, quartz, clay-slate, and ironstone, but most commonly of the first. They form gently rising hills, and may be traced from the banks of the Shannon, in the county of Limerick, through Tipperary and Kilkenny, to the banks of the Suir, whence they range through Carlow, Kildare, and near to the sea shore a little to the south of Dublin: along their entire extent the surface is generally fertile and very picturesque.

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