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especially on the north side, he says, are covered by “ loose blocks 
of the porcelain porphyry of which the hill is formed.’’ 
The Convener can on this point supply information obtained by 
himself some years ago, on the occasion of his ascent of Schehallion. 
He gives the following extract from his geological diary 
“ 1872, August 27. — Went up Schehallion, in company with 
Principal Shairp of St Andrews and Professor Blackie. We began 
ascent at l h 50 s , and reached summit at 5 h 10 s . 
“We went up by a ridge of the mountain running east and west. 
The height of hill I made by aneroid, 3450 feet. I believe Professor 
Hicol made it 3561.* 
“ For the first 1000 or 1500 feet, from where we began our ascent 
(at Braes of Forss) on east side, beds of sand and gravel were 
observed. Hear the top, there were quantities of small pebbles, 
apparently fragments of the hill rock, which is a sort of hard sand- 
stone, somewhat like quartzite. Hear top, observed a few small 
granite boulders . 
“The upper part of the hill, especially on side facing H.W. 
by W. (magnetic), was comparatively smooth, but saw no striations. 
On that side, however, the angles were more rounded than on any 
other side. 
“ On descending, we did not return along the ridge or back-bone 
by which we had ascended. We slanted down in a S.E. direction. 
On the way, I noticed various granite boulders, but none exceeding 
a ton in weight. I chipped some, and found them to be all a fine- 
grained gray granite. These were most numerous, at a height of 
from 2000 to 3000 feet above the sea. 
“ Observed also in our descent, that there were smoothed rocks, 
and chiefly at a height of about 2500 feet. I was struck with the 
fact, that I saw no smoothings above that height. 
“ Observed in the banks of the burns flowing down the south 
side of Schehallion, high cliffs of boulder clay, at a height of about 
1200 feet above the sea. 
“ On showing my chips of the boulders to Principal Shairp, and 
asking if he had ever seen elsewhere rocks of a similar composition, 
he said he had been at Loch Sunart last year, and had noticed 
granite rocks there very similar to that of the boulders.” 
* By Ordnance Surveyors it is made 3547 feet. 
