106 
JOURNAL OF THE GEOLOGICAL SOCIETY OF DUBLIN. 
If we now descend the south side of Glena Mountain, along the 
stream forming the parish boundary, and which falls into the upper 
Lake close to Arbutus Island, we find the purple grits and slates to 
continue for the distance of 2400 feet, and, when last observed, dip¬ 
ping N. N. W. at from 40° to 60°; here we at once pass out of these 
beds and get on green grits, with conglomeritic layers and green slates, 
all lying conformably under the purple beds just passed over; these 
I believe to be the upper portion of the lowest subdivision of the 
Old Eed Sandstone, and the same rocks are persistent to the south, 
with some contortions, till they disappear in the Upper Lake. The 
best section of these lower Old Red beds is seen along the Kenmare 
road, at the base of Cromagloun Mountain; here the grits are often 
bright green, very hard, and many of them finely conglomeritic; 
these conglomeritic layers often consist of small scales of green and 
purple slate: the more decided conglomerates containing pebbles of 
jasper; purple and green slates are rather abundant in this section. 
All observed dips are southward from 35° to 45°, and the total 
thickness of the beds, as measured from near the lower lodge to 
the south of Stag Island Bay, cannot be less than 1500 feet; to this 
may be added 500 feet for beds observed at close intervals to the 
south, so that the section is increased to 2000 feet. As a mass, these 
beds curve round to the N. N. W., dipping from 65° to 75°, forming 
the promontory to the south side of the “Long Range,” andpresenting 
a series of salient angles pointing to the west, and passing through 
the centre of the Upper Lake, to its extreme western termination. 
At the head of the Upper Lake we have the same series of greenish- 
gray and green grits, and green and purple slates; though of course 
higher to the section than those last observed; and as they continue 
up the black valley, and form the base of the mountains on the north 
side, and the mountains themselves on the south, their absolute 
thickness may amount to 5000 or 6000 feet. 
If from the head of the Upper Lake the ascent of Purple Moun¬ 
tain be made, 2730 feet in elevation, greenish-gray grits with con¬ 
glomeritic layers, containing jasper pebbles, green and purple slates, 
with cornstones, are passed over, till, at the elevation of about 1100 
feet, the upper purple grits and slates are again marked, precisely 
similar in character to those described as forming the upper portion 
of Tomies Mountain. All the beds here have a tendency to dip to the 
E. or N. E, at 40°, and the two groups are strictly conformable; 
