of Edinburgh, Session 1880-81. 
247 
Many others were blocked in a similar manner. Plate III., figs. 
1 and 2, represent two of these boulders. 
The boulders on the south side of the ridge, are of much the same 
size, bat are not close to the ridge ; they may have tumbled over 
the ridge by falling from the agent which brought them when 
it stranded on the ridge. The spot now referred to adjoins the 
small stream which flows down from the tanks for supplying 
the Crinan Canal. These tanks a number of years ago burst, 
and many large fragments of rock came down with the torrent, 
but these are quite distinguishable from the boulders above men- 
tioned. 
In reference to the agent which may have brought these boulders 
from the north, there is nothing to suggest the action of a glacier, 
as the trough forming the bed of the Crinan Canal, towards the 
north, unites with an arm of the sea at the distance of only about 
2 miles. That, at some former period of the earth’s history, this 
Crinan Canal trough was occupied by the sea, through which float- 
ing ice might flow, is evident from the well-known traces of old 
sea-margins visible on the adjoining coasts up to at least 300 feet 
above the present sea-level. At the summit-level in this Crinan 
Canal trough, the width of the valley is narrower than anywhere 
else — probably not more than 300 yards, so that floating ice passing 
through this Kyle would easily choke there. 
Mr Jamieson, in one of his papers published in the London Geo- 
logical Society’s Journal, alludes to this trough, now the bed of the 
Crinan Canal, and states that he found smoothed rocks on the east 
side of the valley, and striations running K.W. and S.E. I did not 
see these markings. They are not inconsistent with the theory 
above suggested as to the transport of the boulders. 
2. Oban . — At the south end of the town there is a large number 
of huge blocks of the Old Conglomerate rock, which forms high and 
steep cliffs both east and south of the town. 
On Plate I. there is a sketch of the district occupied by the town 
and by a portion of the hills to the east and south, copied from the 
Ordnance Survey Map. The cliffs on the east side of the town 
(A B C) have nearly vertical fronts, facing the sea. They reach to 
a height of from 120 to 150 feet above the sea-level. At C these 
cliffs take a sudden turn to the eastward. The rocks at B C are a 
2 i 
VOL. XI. 
