176 PROCEEDINGS OF THE GEOLOGICAL SOCIETY, [Feb. 26, 



another proof of what I before stated, namely, that the ice-stream 

 had parted and gone out both to E. and W. I even found some of 

 them to the east of that loch, near Makoul. 



On looking up Glen Spean from the top of one of the hills, I was 

 struck by the greater wear and smoothness of the hill-slopes flanking 

 the valley, below a level of about 2000 feet or so ; and this moulding 

 I could not help attributing to the same agency that had so power- 

 fully scored the rocks of Craig Dhu. 



I have been induced to describe the foregoing case somewhat 

 minutely, because not only is it interesting from the clear evidence 

 it aifords of the extent to which the ice had been developed, but it 

 is further important as affording a good example of a movement from 

 both S. and E., thus enabling us to get rid of the notion which 

 has been so prevalent, that this great glacial action had come invari- 

 ably from the N. and "W. 



I have still to mention a circumstance perhaps even more singular 

 than any I have described, showing the remarkable state of ice- 

 development that had once existed in this region. Just below Craig 

 Dhu there branches off from Glen Spean, in a N. and N.E. direction, 

 the well-known little valley called Glen Roy, extending in that 

 course to the watershed of the Eiver Spey. Near the head of the 

 Roy, the Glen is contracted and nearly closed by some rocky eminences 

 which seem to form its natural termination, and beyond which there 

 is a wide hollow opening into Strath Spey. Wow the surface of these 

 rocky eminences presents clear evidence of glacial action, being 

 rounded off and scored, and also dotted with occasional perched 

 boulders ; but I was not a little surprised to find it quite apparent 

 that the ice had come from the S.W. up Glen Roy, and gone out in 

 a stream towards the wide valley of the Spey. My first thought was 

 that glaciers might have descended from Glen Eggie and other little 

 side-glens which branch off here ; but, on examining the rocks at the 

 junction of the Eggie and the Roy, I found the furrows on the well- 

 moutonneed mica-schist passing right across the mouth of Glen 

 Eggie ; and the strata, which are almost vertical in position, have 

 been so blunted and rubbed on their south-west exposure as plainly 

 to show that the movement came from that quarter ; and high up on 

 the brow of the adjoining hill (which is an extension of that marked 

 Tom Brahn on most of the maps, but known to the shepherds by the 

 name of Craig Corrak) I saw several very large blocks and boulders 

 that appeared to have been shifted or moved some distance by glacial 

 action. 



In Glen Roy itself, owing to the great accumulations of stratified 

 debris, the rock is not well exposed, and, where seen, is often of a 

 rotten, shivery nature ; so that, although I had remark :d some striated 

 boulders, I had not seen any ice-worn surfaces except on the top of 

 Bohuntine Hill, where however I could detect no scores or scratches, 

 although the rock was much ground down. But on returning down 

 the glen my eye caught some suspicious-looking lumps of rock on the 

 flank of Ben Erin that had been bared of their earthy covering by 

 the water of a descending rivulet ; and on scrambling up to examine 



