48 The Rey. S. Haughton’s Notes on Mineralogy. 
mistaken for any other description of rock; they are of a pale 
bluish, or greenish-grey colour, weathering white to the depth 
of several inches, slightly translucent on the edges, of conchoidal 
fracture, and sharp metallic rmg under the hammer. 
The Cornish miners who are acquainted with the mining 
districts of Wicklow and Waterford, consider these rocks as the 
equivalents of their own Elvans, to which they bear no external 
resemblance, though it cannot be denied that they appear to 
exert an equally favourable influence on the productiveness of 
the metallic lodes with which they are associated ; and the re- 
sults of my analyses prove that they have an intimate relation 
to the granitic rocks in their chemical and mineralogical com- 
position. The resemblance in composition to some varieties of 
granite is, indeed, so striking, that it requires but a slight effort 
of the imagination to conceive them as granites cooled under 
peculiar circumstances which prevented the development of the 
usual crystalline structure. 
In some cases, however, these siliceo-felspathic rocks appear 
to be deposited in stratified beds, conformable to the slates and 
felspathic ash-beds with which they are found associated. This 
is particularly the case in the Ovoca district, where the mass of 
felspathic rock is found to lie between dark soft slates of the 
Silurian age, and has never been observed to penetrate these 
slates in dykes. i 
I shall now proceed to the discussion of the analyses of these 
rocks from the Wicklow, Waterford, and Killarney districts re- 
spectively. 
1. Siliceo-felspathic Rocks of the Vale of Ovoca, Co. Wicklow. 
The cupriferous and pyritous lodes of this district have a 
N.E. and 8.W. bearing, and an underlay to the S.E. They 
appear to be nearly conformable to the planes of bedding of the 
slate in which they occur; and they are overlaid to the S.E. by 
a thick mass of siliceo-felspathic rock, which rises into the re- 
markable hill called the Bell Rock, on the west side of the Ovoca. 
The lodes are all dislocated by a left-handed heave coinciding 
apparently with the direction of the Ovoca Valley, and the fel- 
spathic rock partakes of this movement of the lodes. It has a 
stratified character throughout, and in places,as near the Tigroney 
Mine, it assumes completely the character of an ashey-slate, 
weathering perfectly white. 
I obtained specimens of the Bell Rock from Mr. Edward 
Barnes, Resident Director of the Wicklow Copper-Mine Com- 
pany, which were procured by blasting two or three feet into the 
rock, so as to obtain a portion quite free from the action of the 
weather. The specimens are of a pale greenish colour, exceed- 
