153 
of Edinburgh, Session 1878 - 79 . 
the fissure are from 12 to 20 feet in height. The east wall of the 
fissure presents numerous portions of rock well rounded and smooth. 
The west wall is rough and jagged. These appearances suggest the 
action of a current which has grated on the east wall and not on 
the west wall. 
As this is a case exactly similar to that referred to as occurring 
in Barra, and shown by figure 11, it is unnecessary to give another 
diagram. 
(2.) Not far from the foregoing spot there is a coarse-grained con- 
glomerate rock. It is at the junction of three roads. It is the 
same species of rock which forms what is called the Dogstone on the 
avenue to Dunolly, at Oban. The included boulders and pebbles 
are well rounded, and consist of hard gneiss and quartzite. 
Fig. 35 represents a portion of this conglomerate rock, — about 
20 feet across — viz., between east and west, and 5 feet between 
north and south. On the side of the rock facing the N.W. the 
hard pebbles and boulders in the rock have all been ground down 
to an even surface ; whilst on the side facing the S.E. the pebbles 
and boulders retain their original shapes, and stand up above the 
clay matrix of the rock. 
(3.) About 6J miles from Oban, at a place called “ Lailt,” there is 
a boulder of considerable size called “ Clach-a-Currail ” or Perched- 
up Boulder. Its height is 14 feet, and its girth about the middle 
29 feet. Its situation is extremely critical, being on the edge of a 
precipice which goes down at an angle of about 75° for 50 feet. 
The rock of the boulder is peculiar, — a dark chocolate-coloured 
porphyry. No rock of that description elsewhere could the Con- 
vener hear of. 
How the boulder got into the site it now occupies, or from what 
quarter it came, it would be difficult to say. Judging from the 
position of the boulder, the presumption is that it came from the 
S.E., i.e ., down the valley leading up to Loch Awe. But it may 
have come from the N.W., as in that direction there is a valley by 
which it could have floated to its present position. 
About half a mile to the N.E. of this boulder there are fragments 
of what had been a much larger boulder, which a year ago had been 
blown up for building purposes. It was a coarse granite, whilst all 
the rocks in the district are gneiss. Its position suggested trans- 
