609 
of Edinburgh, Session 1879-80. 
to a height of 500 feet, apparently by ice which came through the 
gorge of Tarbert from the west. Above this height the glacial striae 
strike down the slopes of the hill in every direction. 
On the S.E. slopes of the hill, there are portions of the ribbed 
and striated rock which have been torn up, and carried but a short 
distance, then let down and fractured in the fall. 
Clisham and Langa have but few boulders; those on the south 
spur of Langa reach a height of 1400 feet, which is nearly the upper 
limit of the glaciation of these hills. 
While the glaciation of the east and west trenches between the 
Harris hills shows a course of transit from west to east, the valleys 
of the highest hills showed ice to have passed down them from the 
higher level, whatever the direction of these valleys may be. 
West Loch Tarbert . — Though rock does appear between the eastern 
and western arm of the sea which impinge here so closely upon one 
another as to warrant the above common appellation, yet the isthmus 
is for the most part made up of boulder-studded till. One or two of 
the boulders are of a close-grained hornblendic rock, and doubtless 
have been portions of a band of rock of an identical character situated 
a few hundred yards westward on the north shore of Loch Tarbert. 
As the nature and structure of this crypto-crystalline bed is very 
marked and unmistakable, I regard the above as unimpeachable 
evidence of the course of the ice through the pass ; and it must stand 
as such till a similar bed is found on the shores of East Loch Tarbert. 
For such I searched without success, though I found a characteristic 
bed of graphic granite, no fragment of which, however, did I find in 
the till which plugs the throat of the pass. 
Glen Scramble . — This deep glen lies between Gilabhal Glass and 
Skiam Hill. At the bridge which crosses the stream issuing from the 
glen, I found a number of loose masses of an igneous rock, identical 
with a rock forming a dyke coming out above the bridge. These 
masses, therefore, have come down the glen, viz. , from the east ; but 
if they were brought down by ice, there could have been no great 
mass of ice, the distance of conveyance being quite trifling in amount. 
Scalpa Island . — Walking eastward from the village, I fell in with 
a boulder, 7x6x6 feet, of a characteristic granite, butted up against 
the rocky steps of a small knoll of gneiss rocks on its east side, 
about 35 feet above H.W. mark. A sketch of this boulder is given 
