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down their load of blocks. Thus the shores of the island, and the 

 southern plateau as yet under water, became encumbered with vast 

 multitudes of granite boulders, chiefly of that coarse-grained variety 

 constituting the highest mountains. The land, previously moulded 

 into its existing outlines by submarine currents, was next perma- 

 nently raised to that altitude which it retained .for a vast period 

 certainly much more than 2,000 years (Art. 5) till that final 

 upward movement occurred which is marked by the present inland 

 cliff. 



Such is, we think, the only view which the phenomena admit of. 

 Beset with formidable difficulties as regards every region, there are 

 in Arran others of a special kind. As already remarked in the 

 passage quoted from Dr. MacCulloch, the phenomena of Arran must 

 be considered in their isolated aspect, and independent of the main- 

 land. In the Grampians we have ample room in wide open surfaces 

 for the support of snow-fields to serve as feeders of the glaciers (Art. 

 11). In Arran such spaces are limited to narrow and greatly in- 

 clined tracts at the bases of the higher central peaks, and above the 

 cols between the glens, containing^an area which seems too small for 

 the support of such a snow-field. \ Yet) we do not see what other 

 hypothesis can be framed. The existing levels of the surface forbid 

 us to suppose that the whole island, elevated as now, in both divi- 

 sions alike, high above the waters, was wrapped in sheets of ice, 

 across which the granite boulders, as they dropped from the high 

 peaks, were carried onwards in all directions on a slowly descending 

 viscous mass. A continual descent is required to effect such a trans- 

 port ; and this could not exist beyond the limits of the mountain 

 nucleus ; the boulders could not thus have passed to the heights of 

 the southern plateau. This portion, therefore, we are constrained to 

 admit, must have been wholly and deeply depressed below the level 

 of the mountain tract of the north, on which the glaciers rested ; 

 subsequent elevations, marking probably the close of the drift period, 

 established between the two portions of the island those relative 

 levels which still subsist. But the present level of the shores was 

 not yet attained, nor the actual coast outlines as yet carved from 

 the rocky border which broke steeply down all round the island. 

 The sea covered the plains of Brodick and Shiskin, and stretched its 

 winding arms far up the solitary glens. During the slow progress 

 of perhaps forty centuries, the streams from the rugged mountain 

 sides and gentler hill-slopes bore down detritus of granite-sand, 

 slate, and quartz pebbles, and spread them out below the waters of 

 the quiet friths. In sheltered places the tides and waves cut a low 



