Vol. 60.] ANNIVEESABY ADDRESS. XCiil 



same material by the flux and reflux of the tides in the open 

 estuary of the Forth. Were the land to emerge above its present 

 level, a fourth platform would be exposed along this coast, broader 

 and more perfect than its older predecessors above, but showing all 

 the same family characteristics. 



That the daily oscillations of temperature invoked by Prof. 

 Suess in explanation of the Norwegian seter have had their share 

 in the erosion of these Scottish examples, cannot be doubted. But 

 this share is evidently feeble in amount now, although it may have 

 been more considerable during the Glacial Period. More potent as 

 a contributory influence in the erosion of the older terraces, was 

 probably the action of floating ice, driven along the shores by winds 

 and tidal currents. Down to the time of the 50-foot beach, when 

 glaciers in the North of Scotland descended to the edge of the sea, 

 there may have been a good deal of such ice in the more enclosed 

 sea-lochs, where the water, freshened by the discharge of melting 

 snow-fields and glaciers, might itself be covered with a cake of ice. 

 And there was not improbably a good deal more ice in the fjords of 

 Norway. The grinding and rasping action of such ice, driven by 

 gales ashore, has long been remarked. But, in any case, we are 

 justified in regarding the Scottish seter as examples of truly marine 

 erosion, and I can see no reason why those of Norway should not 

 have had the same origin. It is at least clear that the statement 

 that the characters of seter ' are absolutely irreconcilable with 

 what we know of the action of the sea near its surface," cannot be 

 sustained. 1 



Certain features of the extension of the raised beaches throughout 

 Britain appear to be of fundamental importance in relation to the 

 discussion of the problem of the emergence of land. Though so 

 persistent along both the western and eastern coasts of Scotland, 

 these beaches, as is now well known, do not stretch northward into 

 the Orkney and Shetland Isles. Along precipitous sea-fronts we 

 could not expect to meet with them, but among these islands there 

 are endless sheltered inlets and bays which, had they indented the 



1 As far back as 1874 S. A. Sexe expressed the opinion that the sea does not now 

 incise any strand-lines like the old seter (Universitetsprogram, Christiania, 

 1874, p. 38). Eight years previously, after a visit to the Norwegian seter, I was 

 convinced of their marine origin, and suggested that their erosion ' may have 

 been due in large measure to the effects of the freezings and thawings along the 

 oldjce-ibot, and to the rasping and grating of coast-ice. Such, too, may have 

 been the origin of the higher horizontal rock-terraces of Scotland ' Proc. Roy. 

 Soc. Edin. vol. v (1866) p. 543. 



