14 



blocks which we noticed were two of large size and rhomboidal 

 form, one of the Campsie " main limestone," and another of green- 

 stone, showing deep striation and grooving on one side, that on 

 which they must have rested while borne along upon a hard surface. 

 We shall have occasion to refer again to this interesting section. 



Moraines. 



13. On entering the Argyllshire Highlands from Glasgow, at 

 almost any point, masses of detritus are met with, filling the glens, 

 obstructing their entrance, and backing up against the hill sides 

 in flat terraces, with steep fronts towards the river. The glacialists 

 early fixed on these, and all such accumulations in the Highlands, 

 as moraines of the various orders, terminal, medial, and lateral; 

 and not a few have been so described. Mr. Charles M'Laren 

 has published an account of a remarkable one in Glen Messan, a 

 glen entering the valley of the Holy Loch from the west, which 

 he considers a true case of an ancient moraine, such being, accord- 

 ing to his view, comparatively rare in Scotland.* Mr. Robert 

 Chambers, who is somewhat sceptical on the subject of ice as 

 viewed by Mr. M'Laren, coincides with him in regarding this glen 

 as a true seat of moraines. Another case given by Mr. M'Laren is 

 one mile south of Strachur on Loch Fine. One may be seen at 

 Coruisk, near the mouth of the main glen ; another about three miles 

 farther up at Stronlonaig, on a glen entering from the south. The 

 shingle bed at Row Ferry, Roseneath, is fixed upon by Mr. M'Laren 

 as the terminal moraine of a glacier which he supposes to have once 

 filled the Gareloch, crossing from the Loch Goil mountains by the col 

 or summit level, where the scratches are seen. To us this appears a 

 true shingle bank formed by the sea, owing to the peculiar move- 

 ments of the tide at this part. The material is completely sea worn ; 

 and the outlet being narrow, and the extent of water inside great, 

 the tide flows with a powerful current, there being a stream on the 

 west side both at ebb and flood, and an eddy on the eastern. The 

 fact pointed out to me by Mr. Smith of Jordanhill, that the shingle 

 bed rests upon the old boulder clay or supposed glacial deposit, 

 and must therefore be of later date than the rock striation and 

 boulder transport, seems decisive as to the nature of this bank. 

 Other cases of moraines will be found noticed in a recent paper by 

 Mr. Chambers, t 



* Edin. New Phil Jour., vol. i., new series, p. 189, 1855, and vols. xl. and xlii., 1846, 

 1847. 

 f Ed. Phil. Jour., new series, i., 97. 



