^6 Mr. Weaver on the Geological Relations of the South of Ireland. 



northern being one and a half to two feet wide, the middle one about four feet, and the southern 

 six or eight inches ; the interval of slate between the first and second beds being three to five feet, 

 and between the second and third, twenty feet. These beds contain only a few specks of pyrites 

 of iron and copper, and some galena sparingly disseminated. In their arrangement they are 

 nearly rectilinear ; but about ten fathoms north of the northern bed of sulphate of barytes, the 

 slate forms acute-angled inflections, which are exhibited in a horizontal section. 



(38.) In the Audley mines, which are situated about ten miles south-west of Skibbereen, the 

 metalliferous deposits are also contemporaneous with the rock, which consists of slate more or 

 less quartzose, and passing into quartz-rock. The principal workings are on the town-land of 

 Cappagh, conducted on a metalliferous bed, the inclination of the strata being at an angle of 80° to 

 the south. The bed generally consists of quartz, accompanied by purple and green copper ores, 

 but sometimes the quartz disappears, and the metalliferous deposit is confined to the slate alone, 

 appearing in strings and flakes. The bed has varied in its course from an inch and less to two 

 feet and a half in width, forming separate bunches connected by a leader ; and it is occasionally 

 joined and traversed by contemporaneous veins of quartz, most of which are barren, but some 

 contain also interspersed specks of purple and green copper ores. North of this bed is a second 

 of a similar nature, which being only at a short distance, is wrought at the same time. These 

 workings have been extended upwards of seventy fathoms in depth*. 



South of Cappagh mine the slate, after having become vertical, gradually acquires the northerly 

 dip, which prevails also throughout Horse Island, adjacent on the south, varying here from 45° to 60° 

 above the horizon. Here also may be occasionally observed a thin layer of slate (commonly 

 varying from a line to three or four inches in width), which is penetrated with cupreous particles, 

 namely, slight flakes of green carbonate of copper scattered between the laminte and in the 

 fissures of the rock, accompanied by disseminated purple copper ore ; and a similar layer some- 

 times contains also quartz and a small portion of calcareous spar. Quartz veins likewise fre- 

 quently traverse the rock, mostly ranging in the direction of the dip of the slate, and varying 

 from a line to two, three, or four inches wide ; but they often terminate at the distance of two or 

 three feet. They are mostly barren, yet some contain slight flakes of the green carbonate, and 

 specks of the purple sulphuret of copper; chlorite also is not uncommon. In the vicinity of 

 these veins the slate is very quartziferous, and in some of the layers may be incidentally observed, 

 interspersed particles of pyrites of copper and iron. 



A similar diffusion of metallic particles occurs in the slate of the townlands of Filemuck 

 and Ballycomisk, which flank Cappagh on the north ; seven discontinuous layers being dis- 

 posed there, somewhat in an echelon order, and having given rise to as many different trials. The 

 greater part of these trials extended only about ten feet, while one of them was 24 feet in depth ; 

 but the principal, called Ballycomisk mine, was carried down to the depth of 20 fathoms, yet the 

 working in the bottom seldom exceeded six fathoms in length, being that of the main bearing of 

 ore. This was conducted on a bed of quartz mixed with slate, about two feet wide, containing 

 yellow copper ore, specular and micaceous iron ore, some sulphate of barytes, iron pyrites, and a 

 little purple copper ore. The cupreous deposits in some of these trials, have extended occasionally 

 to the width of three or four feet in the rock. 



(39.) Analogous relations to those now described (§.38), occurred at the Ballydehob mine on 



* The Cappagh purple copper ore is sometimes accompanied with bismuth. An intermixture 

 of these substances, analysed by Mr. Edmund Davy, Professor of Chemistry, Royal Dublin So- 

 ciety, yielded 45 per cent, of copper, and 20 per cent, of bismuth. 



