244 S. Hyde — Deep-mining in the South-west of Ireland. 



more, to metamorphic action, of the nature of wliicli, at present, we 

 know but little. But that the Lower, Middle, and Upper Devonian 

 series of North Devon, and the corresponding groups of Cornwall 

 and South Devon (under the name of Killas) are of the same age 

 cannot be doubted. The relation of petrological or lithological condi- 

 tions of the Devonian rocks of North Devon, with those of the South 

 and South-western area of Ireland, is remarkable and almost com- 

 plete. Equally so with the Devonian slates (Killas) and grits of 

 north Cornwall, from Tintagel to Padstow, and the great Middle 

 group, which occupies the country from Trevose Head to near St. 

 Agnes Head ; as well as the lower and great copper-bearing Killas 

 of the South of Cornwall, from Truro to Mounts Bay. These groups 

 of slaty and gritty rocks of the Devonian series in England are 

 represented in Ireland. There are, nevertheless, local differences of 

 high importance, doubtless due to the greatly developed intrusive 

 masses of granite and greenstone, as well as the innumerable elvans 

 which traverse the slaty rocks of Cornwall, and which have doubtless 

 aided in the mineralization of the Cornish killas, imparting to it 

 a character peculiar to itself. All lithological conditions, mineral 

 evidence, and mining experience, tend to confirm the belief that the 

 now two widely-separated metalliferous areas were once one conti- 

 nuous series. The English type having suffered the extremes of 

 metamorphism, through deeply-seated igneous influence, and from 

 other unknown causes, is more highly (so far as hitherto known) 

 productive of mineral wealth. 



It is not a little singular that Ballycummisk appears to be the 

 only mine in which the copper lodes of the district have been deeply 

 and fully developed, or where determined energy has been put 

 forth to grapple with the difficulties of deep mining. No less 

 than eight lodes have been ascertained to occur, and have been 

 proved by the deep adit level driven from the sea at Eossbrin cove, 

 the whole hade, dip, or underlay south 85°, or about 1 in 12. Four 

 of these lodes are well defined, and are worked at Ballycummisk, viz. : 



Pope's Lode; 



The Lady's Vein ; 



Big Vein — the old Baryta Vein ; and 



North Lode. 



Each lode is characterized by particular features, the copper being 

 gray, pui-ple, or yellow in one, yellow in another, micaceous iron, 

 quartz, baryta, and yellow copper in the third, and carbonate of 

 lime, peach, purple, copper ore, etc., etc., in the fourth. The re- 

 maining lodes in the sett are as yet unexplored. All the lodes are 

 parallel, and run east and west, deviating about 32° north of east 

 and south of west. 



A well defined elvan course traverses the sett nearly east and 

 west, and nearly parallel to the No. 1 lode. To the north, and 

 bearing north-east and south-west, occurs the large fault or flucan 

 course, which deviates about 17*^ from the strike or bearing of the 

 lodes, and crosses all the veins except No. 1. This flucan, like the 



