PROCEEDINGS OF SOCIETIES. 89 



exposed, and it is proved to rest on the sandstone. The actual junction of the two 

 rocks is nowhere, that I am aware of, exposed to view; but they may be seen 

 approaching to within a few hundred yards of each other on the line of the Water- 

 ford and Kilkenny Railway, the sandstone being exposed at the western pier of the 

 great Nore viaduct, and the limestone having been cut through close to the Thomas- 

 town station. Besides the great expanse of the limestone, occupying the central 

 and northern portions of the county (and which is, after all, but a limb of the 

 greater limestone formation which covers the central plain of Ireland, stretching 

 from Galway to Dublin, and from Athy to Leitrim), small patches occur at 

 Grannagh, Dunkitt, and Piltown, which are of incalculable value, in an economic 

 and agricultural point of view, supplying a great portion of the primitive districts 

 of the counties of Kilkenny and Waterford with lime. Access is had to the 

 water's edge from the limestone quarry at Grannagh, by a tunnel, running under 

 the public road. It is needless to dwell on the advantages arising from the pre- 

 valence of the mountain limestone in our county ; all our richest lands, either 

 for cultivation or pasture, are situate within its bounds ; when burnt it makes a 

 valuable manure, thus fertilizing the sandstone districts beyond its borders, and 

 (but in a less degree) useful to the limestone tracts themselves. As a building stone 

 it is superfluous to sound its praise; the sculptured ornaments of St. Canice's 

 Cathedral, of Kilcooly Abbey, and many another ancient buildings, show it sharp 

 and uninjured by the lapse of centuries , whilst its black marble quarries, running 

 in a line across this county by Kilkenny, Farmley, and Callan, afford an abundant 

 and elegant material for internal ornamentation. The mountain limestone of 

 Kilkenny presents many varieties. Of these, it will be sufficient to enumerate, 

 beside the black marble already alluded to, the brown spar and magnesian limestone. 

 1. The brown spar is a dove-coloured and highly crystalline limestone, altered by 

 fire, and on its way, as one may say, to be made white marble ; for the Carrara 

 marble, of whose spotless purity sculptors have taken advantage in every age, is but 

 limestone altered by the action of heat under great pressure. The old geologists 

 called the brown spar sidero-calcite, or iron- limestone ; and as such you will find it 

 mentioned in Mr. Tighe's admirable survey of the county. The localities where 

 this rock is apparent reach from Archer's Grove, where it forms an extremely 

 picturesque line of cliffs, across the Nore, showing again at Lavistown and Dunbell, 

 in the cuttings of the Waterford and Kilkenny Railway, from thence stretching 

 towards Gowran, where it rises into the elevation known as Freestone Hill, and so 

 across to the base of the Johnswell mountains, where, at Kilcomar, it is well defined. 

 At Riverview, a small stream separates the dark-blue limestone from the brown 

 spar, in a very remarkable manner, the different rocks coming quite to the brink of 

 the stream at each side. The researches of the government geological survey, 

 which is at present being carried on in Ireland, have, as I am informed, brought to 

 light a very curious cause for this altered limestone. It appears that it lies in the 

 direction of a great fault, or upheaving of the earlier sedimentary strata, caused by 

 the protrusion of the plutonic rocks, which form the mountain ranges of Carlow and 

 Wexford ; from this crack, or fault, there would be an emission of the central heat, 

 which, acting from below on the limestone, and under the pressure of a superincum- 

 bent ocean, would convert these rocks which came in contact therewith, into a 

 species of marble ; and it is remarkable, that the other marbles of our county strike 

 across the district close to, and in a line with, the brown spar. 2. The magnesian 

 limestone covers a large tract of country, within which Ennisnag, Annamult, Flood 

 Hall, and Kells, are situated ; and a patch of the same rock occurs near Pil- 

 town, in the barony of Iverk. This rock differs chiefly from the other calcareous 

 strata in containing a large quantity of flint in its composition, sometimes exhibiting 

 in the form of clusters of very beautiful prisms of quartz ; and, in consequence, 

 makes a bad building stone, and worse lime. In compensation for these defects, the 

 magnesian limestone often contains ores of lead and silver ; and a mine of this 

 metal was worked in this district, with considerable success, at Knockdrina, over 

 Flood Hall, as mentioned by Mr. Tighe in the work already quoted. A magnifi- 

 cent silver cup, the property of this mine, was kindly entrusted to this Society by 

 Mrs. Flood, to accompany the geological specimens forwarded by this institution 

 last summer to our great National Exhibition. 



