Vol. 60.] ANKIVEKSARY ADDRESS. Xrvii 



(ii) Submergence. 



Of the various kinds of proof of the submersion of terrestrial 

 surfaces furnished in these islands, I will refer only to two : first, 

 the extension of land-valleys beneath the sea ; and, secondly, the 

 existence of what are known as Sunk Forests. 



1. That the fjords of Norway, the sea-lochs of the West of 

 Scotland, and the harbours or inlets of the West of Ireland were 

 originally valleys on the dry land, although now deeply submerged, 

 has long been an accepted belief among those geologists who have 

 specially considered the subject. The interval of time which has 

 elapsed since this submergence has not sufficed to till up with 

 sediment these submarine depressions. By a study of the sea- 

 charts, we can still trace the winding curves of the ancient valleys, 

 and can even here and there detect among them the basins which, 

 when the present sea-bottom was a land-surface, were filled with 

 freshwater lakes. On the sea-floor to the east of our own country 

 and of Scandinavia, such relics of subaerial denudation are less 

 imposingly preserved, yet evidence of the submergence of land- 

 valleys has been noted there also. It must of course be re- 

 membered that the land on that side is of much lower altitude than 

 on the western coasts, that the ground slopes gently under the sea, 

 and that the valleys are comparatively insignificant depressions on 

 its general surface. Moreover, the more abundant drainage on the 

 longer slope east of the watershed, and the much greater develop- 

 ment of Drift on that side, leads to a far more copious discharge of 

 sediment into the shallow North Sea and the Gulf of Bothnia, and 

 the submarine prolongations of the old land-valleys are thus apt to 

 be buried under recent accumulations of detritus. There may, 

 however, perhaps be another cause for the contrast between the 

 profoundly indented and precipitous western coast and the com- 

 paratively low and monotonous trend of the eastern coast. I have 

 long been disposed to believe that the submergence has been greater 

 towards the west than towards the east. In the prolongation of 

 the West-Highland sea-lochs on the floor of the Atlantic outside, 

 the original land-surface sometimes lies 600 feet or more below the 

 present sea-level. The same fact presents itself in Norway, as in 

 the striking case of the sinuous submerged valley which continues 

 the line of the Stor Ijord, south of Molde, for some 50 kilometres 

 (or 31 English miles) seaward, and descends to a depth of 1000 feel- 

 below the surface. If the submerged land-surface of North- Western 



