188 
Mr, Weaver on the 
to be in immediate contact with mica slate, on the eastern side 
of the Glenisloreane stream ; for quartz rock constitutes the greater 
part of Coolakay and Long hills. It very soon alternates, however, 
with clay slate, as may be observed on the eastern side of Coola- 
kay hill ; and between Long hill and the western foot of Great 
Sugar Loaf, is a considerable body of purplish and greenish clay 
slate, with a southerly dip. On descending the eastern ravine in 
this quarter, (through which the principal outlet is found to the 
north for the waters of the marshy land on the south), we find 
the stratified rocks, already described, well exposed, forming in the 
lower part banks 50 to 80 feet high. The general range is east 
and west, with a southerly dip under an angle of 75°. The com- 
pact beds in the upper part of the ravine are from one to three feet 
in thickness, and the slaty from one to six and eight inches ; while 
in the lower part they vary from two to five feet wide. In a few 
of the latter I discovered some calcareous spar intermingled with 
the rock, but in very small quantity. This occurrence, a similar 
one on the eastern side of Bray Head, and an analogous appearance 
in the trap of Arklow rock, afford the only instances in which I 
have met with carbonate of lime as a constituent in this extensive 
mountain tract. 
§ 81. The cone of Great Sugar Loaf is steep on every side, rising 
under an angle of 35°. In a lateral point of view, it appears as a 
narrow backed ridge of a serrated aspect, 50 or 60 yards in length, 
rising up into a sharp crest. The cone and great body of the moun- 
tain consist of quartz rock, but in descending to the north-western 
flank, greenish clay slate becomes observable, dipping into the hill • 
and in approaching the northern face of the defile, which separates 
this mountain from Stilebawn hill, we encounter alternations of the 
rocks already mentioned. Their range is 25° north of east and 
