I860.] 



JAMIESON DIUFT, ABEKDEENSHIEE . 



363 



These furrows were not quite horizontal, but sloped somewhat 

 with the inclination of the ridge, the north ends pointing down 

 towards the Tummel. 



Land-ice sliding down the hill might give rise to these markings, 

 or floating ice coming from the north during the submergence of the 

 country; but no glacier moving down the Tummel could effect them, 

 as the direction of that valley is here E. and W. 



Fig. 12. — Section across the Bed of the Stream, showing strice on the 

 vertical surface of the rock. 



Stream, E . 



I. The stria;. 2. Drift. 



In the valley of the Tay at Aberfeldy, I noticed striae and grooves 

 on the gneiss below the drift, a short way up the banks of the stream 

 that gives rise to the well-known Falls of Moness. Now the direc- 

 tion of this stream is here almost N. and S. ; whereas the glacial 

 furrows pointed due W., conforming to the strike of the main valley 

 of the Tay. 



With regard to the striated rock-surface beneath the great Pleis- 

 tocene bank on Meal Uaine, the direction of the grooves and furrows 

 also coincided with that of the main valley in that quarter, their 

 strike being N.W. and S.E., transverse to the course of the little 

 rivulet, and also to the strike of the rock}' strata, which is here N. 

 60° to 70° E., dipping almost vertically. 



Sometimes these grooves ran horizontally along the face of the 

 humps of rock, which were much ground down and rounded off. 

 Where the strata were of coarse quality, the markings consisted of 

 rude scores and furrows ; while the harder, fine-grained quartz was 

 polished until it glanced again, with numerous fine, needle-like 

 scratches, coinciding in their general direction witli the scores on the 

 coarse gneiss. 



Now, as the situation of these markings in this case is in a deep 

 sheltered hollow, protected both to N. and B. by protruding buttresses 

 of rock, it struck me forcibly thai do floating iceberg could well have 

 elicited them, for it would have grounded, on these projecting ridges ; 

 while it seems further difficult to conceive how any Large island of 

 ice could have approached at all from the N.W.. 90 environod La the 

 spot by hills in that direction. 



Altogether it seemed to me more like the action of a glacier that 

 had occupied the \ alley previous to the marine drift, and whose 

 plastic mass could adapt itself to all the sinuosities of the surface ; 



2 1 2 



