809 
of Edinhurgh, Session 1883 - 84 . 
angular, 22x16x16 feet, its base resting on the plateau, and its 
top leaning against side of hill {Lithograph No. 16, Plate IX.). 
On ascending to summit of hill (which reaches to height of 400 
feet above sea) Convener found several boulders of red granite. 
Mr Allan McDonald (schoolmaster) doubts the theory that the 
red granite boulders on “Dun I ” Hill came from the Ross of Mull ; 
— firsts because the rocks at Ross of Mull do not reach to so high a 
level as 400 feet ; second, because, as regards the 400 ton boulder, 
“ Dun I ” Hill is situated between it and the Ross of Mull, so that 
transportation from Ross is hardly conceivable. Ross of Mull bears 
from boulder S.S.E. 
The smooth faces of the rocks in Iona, front N. by E., the rough 
faces front south {Second Report, p. 156). 
In a subsequent year (1878) the Convener again visited Iona, and 
went to look at the large boulder on “ Dun I.” He then observed 
that the boulder was composed of coarse-grained red granite — more 
coarse than the boulders on east side of island previously referred 
to. The prevailing rocks of Iona are a fine-grained gneiss, approach- 
ing in many places to clay slate. 
The boulder on “Dun I” Hill seemed to indicate that it had been 
brought by some agent from a north-westerly point, which agent had 
stranded on the hill, and stuck there, till boulder dropped from it. 
Captain Stewart of Coll was with Convener when latter examined 
the boulder. On examining the portions broken off, as also another 
small boulder lying below, exactly similar in composition, Captain 
Stewart at once exclaimed — “ This is Coll granite.” 
In reference to this suggestion, it is to some extent confirmed by 
the fact, that the island of Coll bears about N.N.W. from Iona, and 
is distant about 20 miles. But the Convener, having visited Coll a 
few days afterwards, did not fall in with any granite rocks there. 
They were all gneiss, with only occasional veins of granite. But he 
did find granite boulders in Coll, somewhat similar in composition 
to the large boulder on “ Dun I ” {Fifth Report, p. 4). 
A well rounded boulder of Conglomerate was found by Convener 
on east coast of Iona. Heard that similar blocks occur on west shore 
in St Columba’s Bay. There are no Conglomerate rocks in Iona. 
The nearest spot is said to be Inch Kenneth Island (on west of Mull), 
where, according to Macculloch, it forms cliffs about 100 feet high 
