Geological Relations of the East of Ireland . 
177 
these rocks at the surface contain a great deal of brown iron ochre, 
arising from the decomposition of hornblende and iron pyrites, 
and some are traversed by contemporaneous veins of quartz. The 
principal bed is situated in the park and occupies a breadth of about 
fifty fathoms, being composed of a greenstone, the hornblende of 
which rather predominates in the western part, while in the eastern 
the two ingredients are closely incorporated. 
§ 69. Ballinacor hill, (see PI. 8. No. 7,) may be considered 
as the south-western extremity of the Ballinvallow range, and 
Glenteigue hill as the south-eastern; the latter being situate imme- 
diately upon the coast. In the former is a bed, some fathoms wide, 
near the road to Arklow, which partly consists of granular felspar 
stained and dotted with hornblende, and in part of felspar and 
minute slender prisms of epidote. Glenteigue hill is wholly com- 
posed of trap, and of rocks allied to it; and in traversing the hill 
from west to east we perceive their connexion. On the western 
side, on the road leading to Redcross, we observe clay slate ranging 
north-east and south-west, dipping 80° to the south-east, and sup- 
porting trap in a conformable position. The composition of the 
clay slate at the point of junction is visibly affected by the proximity 
of the trap ; and the latter rock to the eastward of the clay slate 
consists of an intimate mixture of hornblende and felspar, with much 
disseminated pyrites, and occasional crystals of felspar and horn- 
blende ; its colour varying from blackish green to greenish grey 
according to the state of intermixture. On the western brow it 
passes into greenstone slate ; and exhibits also a tendency toward 
the rude columnar form. Higher up, this rock verges more and 
more toward felspar porphyry, and in the eastern part of the hill it 
graduates into a simple compact felspar. The former passes 
through various shades of green, grey, and yellow ; the latter is 
Vo l. V z 
