32 Mr. Weaver on the Geological Relations of the South of Ireland. 



and outcropping to the north at an angle of 40° to 45°, but in descending to 

 the southj gradually flattening to an angle of 6° or 7°, and on approaching the 

 lake becoming absolutely horizontal. The line of division thus marked in the 

 section, between the two descriptions of limestone, serves to indicate correctly 

 their coinciding stratification ; and by the miner it is familiarly termed the flat 

 bed. The juxtaposition of the two rocks is, in most cases, so close as scarcely 

 to admit the blade of a knife ; but in some places the line of separation is 

 expanded to a few inches, and, though very rarely, even to two or three feet; 

 the interval being occupied by clay, either wholly barren, or containing occa- 

 sionally iron pyrites, or disseminated particles of copper ore, derived from the 

 deposits above. 



The metallic deposits, thus described, occur in the blue limestone mass, and terminate in 

 their descent to the southward on reaching the flat bed, never penetrating into the subjacent, silice- 

 ous limestone. The galleries, drifts, and sinkings proved this fact. The two former (distinguished 

 in the plan and section by narrow lines) are wholly driven in the blue limestone, the siliceous,lime- 

 stone forming their floor -, and in the deep level (marked by broader lines) tlie siliceous limestone is 

 chiefly cut into. The new engine shaft penetrated 44 feet into the siliceous limestone, and a bore- 

 hole from its bottom went 31^ feet deeper; and a cross-cut was driven from Cock's shaft wholly 

 in the siliceous limestone under the Blue Hole, and connected therewith by a bore-hole ; yet by 

 none of these operations was a particle of ore found in this rock. 



The experience thus gained prognosticated an early termination to this mining adventure, un- 

 less further discoveries could be made either within or beyond the then existing excavations. 

 With the former view, drifts were opened from the Cliff' shaft to the north-east and east ; and by 

 eight bore-holes the ground was also searched in the south-eastern quarter ; but by neither 

 operation was any discovery effected. Galleries were likewise extended to the westward, and by 

 one of these, productive ground was laid open, which led to the excavation of a whole mass of 

 rock, containing disseminated ore, from the flat bed up to the very surface, as indicated by the 

 darker-coloured, triangular space marked on the plan. 



To try the ground effectually to the north of the mine, both in the blue limestone and the sub- 

 jacent siliceous limestone, the following measures were adopted : (See Section.) 1st, A cross- 

 cut was driven twenty fathoms north from No. 8 shaft in the blue limestone, and a winze or pit 

 was then sunk in the siliceous limestone five fathoms deep, from which a bore-hole went five fathoms 

 deeper. 2nd, Another cross-cut went north-west nineteen fathoms, being fifteen fathoms beyond 

 the ore ground, and a bore-hole was put down beyond it. 3rd, A series of bore-holes, thirty in 

 number, were distributed over the north ground, descending in all cases through the blue lime- 

 stone into the siliceous limestone, and in a few instances perforating the latter rock to the depth of 

 five fathoms. 4th, Trenches were cut down to the blue limestone rock, and extended to the north 

 neai-ly to the siliceous limestone, which crops out there at the surface. By none of these re- 

 searches was any discovery made. 



I must here observe that had any true lode or rake vein, upon whatever range, existed within 

 the precincts of the mine, it must have been discovered in the course of working ; and the 

 same assertion holds good with respect to any vein which might have ranged north and south in the 

 ground, north of the mine ; and with regard to any vein upon an east and west range in the north 

 ground, the trenches would have made its discovery. Again, had any irregular metallic deposit, 



