266 ScientifiG Proceedings, Royal Dublin Society. 



termed, " placer mines." While gold in situ (i.e. in the original 

 rock or matrix) even in minute quantities, is up to the present of 

 rare occurrence, and few localities have been recorded. Of these 

 may be mentioned : — 



A quartz vein, in the Cambrian rocks on Bray Head, Co. 

 Wicklow, which within the past few months has been proved 

 auriferous by Mr. Francis Codd, at the Koyal College of Science. 

 This occurrence is of special interest, as it appears to be the first 

 record of an auriferous quartz vein in Ireland. The rocks in 

 which this vein occurs are green grits, and slates, across the strike 

 of which it cuts at angle of about 60°. There would seem to be 

 some similarity between these rocks and those of Merionethshire, 

 where gold has been worked near Dolgelly and Barmouth. 



The late Sir Richard Grifiith, in his list of mineral localities in 

 Ireland, states that the gossan of the Dhurode copper lode at 

 Carrigacat,* on the south shore of Dunmanus Bay, is auriferous 

 (Cork, Ordnance Survey of Ireland, six-inch maps, sheet 147.) 



The pyrites of the Ovoca (co. Wicklow) mineral channel, has 

 long been known to contain traces of gold, especially that of 

 Ballymurtagh, Cronebane, and Connary. At Ballymurtagh the 

 gossan is the richest part, but it is also found in the pyrites lode ; 

 it is also stated to occur in the ochre that separates from the 

 drainage waters of these mines. 



At Upper Cronebane and Connary there appears to have been 

 a richer deposit, from which the gold was extracted, as M. Charles 

 Coquebert, writing, about 1794, a description of these mines in the 

 "Journal des Mines," No. XVI., states tha,t at Liverpool, they 

 extracted by liquation, from this pyrites, " a certain proportion of 

 silver, and this silver contains 0'01146 of gold."-f- 



In some parts of the lode at Ballymurtagh, Upper Cronebane, 

 and Connary, an ore is found called " Kilmacooite," which has 

 been described as "a peculiar combination of sphalerite, argen- 



* There are specimens in the College of Science Museum from this locality. These 

 specimens consist of " auriferous " gossan associated with hard white crystalline quartz 

 containing " vugs " filled with yellow ochre. 



1 1 am informed by Captain Argall that when the Wicklow pyrites Was used exten- 

 sively in England, from the pyrites ash an auriferous silver was extracted at St. Helens 

 by a liquid process, which was worth from 8s. to lOs. per ounce ; any Wicklow ore was 

 used. 



