250 
THE GEOLOGIST. 
(PI. XIII.), and there is a superstition that on All-Hallow Eve this 
mass floats off* into the lake, returning to its present resting-place ere 
cockcrow. This remarkable block consists of a series of purple grits, and 
thin purple earthy layers, and now measured roughly is 40 x 25 x 16 
feet, representing a bulk of about 10,000 cubic feet, and weighing 
about 1100 to 1200 tons. Originally this mass was much larger, 
as large flakes have fallen off" its sides from the result of atmospheric 
action. 
On the Carboniferous slate district to the S.W. of Dunmanway, at 
the summit, marked 964 feet to the west of Millane Hill, there is a 
perched boulder of hard light grey gritty slate, measuring 6x4-^x2^ 
feet, which is known to the peasantry by the name of" Gallaun Keogh." 
To the north of Dunmanway in the Townland of Gurtanure, and at 
the junction of the Caha with the Bandon River, a rocky boss aff'ords 
some very interesting examples of "roches moutonnees " and glacial 
striae. Here we find purple grits weathering into small pinnacles on 
the lines of the dip, the cleavage and the cross joints, the sides and 
angles of which are rounded and polished and marked with well- 
defined horizontal striae. On the level polished surfaces of rock, we 
find the same peculiarity of form in the scratches as before noticed. 
They are fine at the end pointing to the N.N.W., and blunt at that 
pointing to the S.S.E., thus clearly indicating the direction from 
which the current came which floated the ice-masses forming them. 
The horizontal markings have not however this peculiarity, but are a 
series of fine groovings and sharp scratches. 
Over the Carboniferous slate to the south of Dunmanway the 
compass bearing of the glacial striae is generally the same as that* 
over the Old Red Sandstone, and the mountainous district to the 
north. This is very well seen in the horizontal and smooth rock 
surfaces to the north of Ballinacarriga Lough, at an elevation of 339 
feet, where the strife run N. 20 "W. and S. 20 E., the thin end of the 
scratches being presented to the former point. 
The accompanying illustration of a perched boulder from near 
Dunmanway (PI. XIV.) is interesting in many respects ; it shows 
how readily the sandstone yielded on the planes of the slaty cleavage 
to what must have been the sudden concussion of an iceberg ground- 
ing on such a submerged inequality in the sea bottom as this rocky 
boss must have been. The view is taken looking somewhat to the 
westward. The general form of the rock when it was submerged in 
the glacial sea must have been very nearly the same as now, one side 
