170 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 17, 



been effected subsequent to the deposition of the newer sandstone. 

 It is evident that any process of denudation would necessarily first 

 affect the higher, or outer, parts of the strata, which, if the metamor- 

 phic action came from below, as we must assume, would of course 

 be the softer, and less altered. The parts left behind would, for the 

 same reason, and also from the greater power of resistance, be the 

 harder and more metamorphic. In conformity with this view, we 

 observe that the smaller fragments of the older red sandstone em- 

 bossed among the gneiss mountains on the east are far harder than 

 the larger and more continuous masses of the same rock. 



It must also be remembered that the denudation of the older red 

 sandstone, though begun at this early period, was continued long 

 after its close, or, to speak accurately, is still going on even at the 

 present time. These small spots of newer (Triassic) red sandstone 

 are indeed but very inadequate representatives of the enormous mass 

 of matter which has evidently been removed from the once con- 

 tinuous platform of the older sandstones. The amount of the calca- 

 reous matter in the newer beds is important, as showing that, at the 

 time of their formation, the upper or limestone portion of the series 

 was furnishing more than a proportionate share of the material, and 

 hence probably that the denuding processes had only been going on 

 for a short time. But the same agents of change which affect the 

 higher and older rocks must have acted also on this newer deposit ; 

 and we are therefore justified in regarding the portion that is now 

 seen as a mere fragment of what it may once have been. 



Glacier-moraines. — I have several times already referred to the 

 immense number of large boulders of gneiss and other primary rocks 

 spread over the surface of this district. In general they are arranged 

 in no apparent order. There is, however, one remarkable exception, 

 which I must shortly notice, as probably indicating the mode in which 

 some of them at least have been transported from their native moun- 

 tains. Near the top of the acclivity between Loch Greinord and Loch 

 Ewe, the road crosses an enormous ridge of stones rising up abruptly 

 from the moor. It runs in a line from E.N.E. to W.S.W., and at its 

 northern extremity is met nearly at right angles by another similar 

 ridge, running S.S.E. towards the high mountains north of Loch 

 Maree. The outer or north-western side of the ridge consists of 

 large loose angular stones, and the interior of the mound of similar 

 stones mixed with sand or clay. These stones were principally white 

 and grey gneiss, hornblende-rock, and red sandstone, but I also ob- 

 served one or two specimens of mica-slate, containing garnets. They 

 thus consist of the very materials which the mountains on the south- 

 east would furnish to any powerful denuding agent. And the form 

 and arrangement of the stones left no doubt in my mind that this 

 agent had been a glacier, cradled in the mountain-valley in which 

 Loch Fuir now lies. The first ridge would then form the terminal, 

 the other the lateral moraine. Some other peculiarities confirm this 

 view. The ground behind the ridge slopes down to a small lake, 

 lying as it were in the mouth of the opening in the mountains whence 

 the icy stream has flowed. The stones therefore must have been 



