178 Charles Maclaren, Esq., on Grooved and Striated Bocks 



springs of the Spean, the Leven, and the Orchay, from those 

 of the Spej, the Ta}', the Earn, and the Forth. And the force 

 must have resided in some substance which admitted of ac- 

 cumulation to a vast extent, for the abrasion produced by it 

 can be traced to the height of more than 2000 feet. Now 

 water could not be so accumulated here except in tJie form of 

 snow and ice, and even if it were so accumulated in the liquid 

 state, it could not, as has been shewn, produce the eifects 

 fairly ascribable to it. These effects are such as cannot be 

 ascribed to any agency known, except that of glaciers, aided 

 perhaps, in some cases, by floating ice. 



Professor Forbes, in his paper on the Cuchullin Hills in 

 Skye (in No. 79 of this Journal), describes well-marked groov- 

 ings on their sides, radiating fi'om the hills in different direc- 

 tions, as from a common centre, so disposed, he observes, 

 that they can be accounted for neither by mountain lakes 

 nor great oceanic waves, nor by any great agent known but 

 glaciers. 



I have not yet examined the channels of the Spey, the 

 Findhorn, or the Dee, but I have no doubt that groovings 

 pointing northward and eastward, will be found in them. I 

 infer that the mountainous country, west of the Great Glen, 

 from Morvern northward to Sunderland, was another centre 

 of glacial action ; and further, that the Great Glen itself was 

 probably the seat of a glacier which found an exit by its 

 north and south ends, and was fed by the smaller glaciers 

 flowing into it from the east and west. 



The strife, groovings, and kindred phenomena, in the great 

 central valley between the Frith of Forth and the Frith of 

 Clyde, and on the hills contained in it, do not seem to admit 

 of explanation on precisely the same principles. The strife 

 in this district have a direction always approximating to east 

 and west, and there is good evidence to shew that the abrad- 

 ing agent moved eastward. No glacial markings have yet 

 been discovered, so far as I know, running in lines at right 

 angles to the sides of the Pentlands, such as glaciers in the 

 ti'ansverse valleys would produce. On the other hand, the 

 striae found on their summits and flanks (arrows 24, 25, 26), 

 either run along the chain, or hold their course independently 

 of it. 



