310 Scientific Proceedings, Royal Dublin Society. 



ever, possible that, if sunk on still further in depth, the walls- 

 might again separate. 1 



The south lode occurs in Kilmacoo and the Magpie, it being 

 principally " blue ground," in which are the veins and pockets of 

 Kilmacooite or bluestone. This peculiar mineral appears to be an 

 admixture of the sulphides of zinc, lead, iron, copper, antimony, 

 arsenic, and silver, with a trace of gold ; but it varies greatly 

 and rapidly. It was known in Weaver's time ; as the Coppery 

 ore in Madame Stephens' lode is mixed with it; while a vein 

 was cut in the "Lodge level." Weaver seems not to have 

 been able to utilize it, while at the present day it cannot be 

 economically reduced. At the present time the typical ore has 

 only been proved in the places above named ; but a variety was 

 found in West Cronebane by Argall, and Haughton mentions a 

 variety that occurred in Ballymurtagh, the latter in places being* 

 very auriferous (page 206). If, however, the economical reduction 

 of this ore is hereafter understood, it is probably that elsewhere 

 in the courses of " blue ground " it may be found. 



A careful analysis of this ore is most important, as, on account 

 of the various constituents and their peculiar relations to one 

 another, hand specimens are very different, some being very rich, 

 others very poor ; and unless the greatest care is taken in selecting 

 specimens for analysis, the results may afterwards be most disastrous 

 to the well-being of a mine. This caution is necessary, as the 

 analyses published show that in most cases the ores examined were 

 picked rich specimens, which although of interest to the mineralogist, 

 are pernicious to the mine, as they lead to false hopes, which can 

 never be realized. The Magpie has been so-called from the black 

 and bluish-white ground found in the lode associated with the 

 ores. 



To the westward of the Magpie, between it and West Crone- 



1 In the deepest working (Williams' shaft, Tigroney) the walls appeared to be again 

 separating. In some of the Cornish mines when the Copper lode had died out, on 

 sinking deeper, tin ore was found. This appears to be a consideration in connexion 

 with the future of these mines, more especially as tin must exist somewhere in the 

 county, having been found in the "streamings'.' for Gold. Furthermore, in the Magpie 

 shaft the lode in depth was cut out by a Granyte protrusion ; and, if the lode continues 

 in depth, the mineral contents might possibly change. If these mines hereafter gave 

 new riches in depth, they might be economically worked, by driving up "Weaver's- 

 deep or "Boat level." 



