141 
of Edinburgh , Session 1872 - 73 . 
Bounded boulders also occur on these rocky knolls, but not so 
frequently as angular boulders. 
In connection with the fact of boulders being much clustered 
on and round rocky knolls, it may be noticed that boulders of large 
size, and especially angular boulders, are said to occur more fre- 
quently at high levels than at low levels. 
On this point reference may be made to the report by one of the 
Ordnance surveyors from Boleskien in Inverness county, in which 
it is remarked that the hills in Stratherick reach to a height of 
2900 feet, that the boulders are often perched on isolated hills, 
and that few boulders occur there below the level of 2250 feet.* 
One of the largest angular boulders seen by your Convener (in 
Grlen Lyon, Perthshire, and weighing above 100 tons), is at a 
height of 2500 feet above the sea. 
It is proper, however, to add, that clusters of boulders do likewise 
occur at or bejmnd the mouths of valleys. In the Lochaber district, 
opposite to Loch Treig, in Spean Valley, there is a great accumu- 
lation of large boulders. So also in the valley of the river Nairn, 
to the east and below the mouth of Flichity Valley, there is a 
similar accumulation. In both of these cases the boulders lie on 
the top of debris, having all the appearance of moraines. These 
accumulations of boulders may be ascribed with great probability 
to the operation of glaciers. But that explanation cannot apply 
to clusters of boulders on or near the tops of hills. 
3. Special notice deserves to be taken of the fact, that boulders 
of all sizes occur on islands, though in these islands no rock exists 
of the same nature as that composing the boulders. 
In the First Keport of the Committee several cases of that kind 
were reported from the Hebrides, as also from Orkney and Shetland. 
In the statements appended to this Beport, additional examples 
are reported. 
Mr Campbell of Islay, in a document given in the Committee’s 
last Beport, says that many of the boulders on the western islands 
are u perched on hill tops,” and have come from the northward in 
a direction “ parallel to the run of the tides.” 
Appended to this Beport, there is a similar opinion expressed, 
founded on the appearances in the small island of Foula (Shetland). 
* See Inverness, page 157 
