280 Proceedings of the Royal Society 
the Stob a Cliearchaill ridge were found, up to their respective 
summits. 
On the Bein Bhan hill a ridge runs up from the north-east 
towards its summit, on which ridge one of the boulders was found 
in so peculiar a position, that a sketch of it was taken, the shading 
being tilled in by Mr Colin Phillip (an artist) who accompanied 
Professor Heddle. (Plate III., tigs. 5 and 6). 
The boulder consisted of six pieces, the smallest being lower- 
most. The question arose, What had fractured the boulder h 
Atmospheric action did not seem the agent. The surfaces of the 
fragments where rent, were somewhat conchoidal in shape, and 
indicated rupture by violence done to the under part of the 
boulder. The most probable explanation which suggested itself 
was, that it had tumbled off the raft which carried it, and, being 
of great weight, had broken by concussion against the rock of the 
hill. The size of the boulder was 8x7x6 feet. 
If this boulder formed part of the stream which had crossed the 
valley now occupied by the Linnhe Loch, it must have been floated 
on ice, — in which case the fall of the boulder would be through 
water. At the sea-bottom, the concussion upon rock might still 
produce a fracture of the boulder ; and the fragments would remain 
closer to one another, than if they had fallen in air. 
A representation of the hill ridge on which the boulder rests, and 
of the fragments composing it, is given on Plate III. fig. 5, and 
indicates the position of the boulder on the JST.E. ridge of the hill. 
Pig. 6 represents the boulder in its different fragments lying on a 
notch of the hill. 
The Convener who has made the foregoing extracts from Profes- 
sor Heddle’s notes, thinks it only due to him to mention that these 
extracts give no idea of the enormous amount of labour which the 
Professor has undergone in his boulder researches. During the 
summer and autumn of 1880, he must have walked several hundred 
miles over districts many of which are not accessible to ordinary 
pedestrians. This is shown by the tracks of his surveys laid down 
by him on the ordnance maps, and by the names given in his notes of 
the hills and valleys visited. A great part of these expeditions were 
unsuccessful and disappointing ; but he has specified them in full 
detail, in case the committee might deem it useful to record in their 
Report the districts visited, for the information of future observers. 
