370 proceedings or the geological society. [Feb. 15, 



rear a perpendicular front of 1000 or even 1500 feet, as at Lochnagar 

 and Cairntoul ; and it will be found that their base is frequently at an 

 altitude of 2200 to 2500 feet. Wandering along these lofty walls 

 of granite, the thought sometimes struck me that in them I saw the 

 ancient sea-cliffs of this glacial sea, and that here its chill waves were 

 staid. Afterwards, on looking over the beautiful plates of Professor 

 Forbes's book on Norway and its Glaciers, I was impressed with the 

 resemblance of some of the scenes along that iron-bound coast to the 

 rocks and corries of these Highland mountains. 



In order to obviate the objections that naturally arise against such 

 a change of level as I have hinted having taken place in a geo- 

 logical period comparatively so recent, I may call to mind that the 

 marine Pliocene of Sicily rises 3000 feet above the present coast-line ; 

 and further, that Sir Roderick Murehison and other eminent geologists 

 invoke a like change of level for the Alps (Geol. Journ. vi. p. 66). 



The conclusions which I have above drawn might lead to a very 

 interesting inquiry as to how the present flora and fauna overspread 

 the country ; for there can be little doubt that their introduction, as a 

 whole, dates from the close of the marine- drift-period. But this would 

 be quite beyond the scope of the present paper ; and I shall only point 

 out how highly desirable it is that a clear distinction should be made 

 between the group of Mammalia of the period antecedent to the 

 drift from that of the period which followed it in this country : for it 

 would seem to be the case that the two assemblages, although both 

 geologically of recent date, are yet severed by a long stretch of time. 

 § 7. Combining the observations of this and my former paper, 

 I am inclined to think that the following course of events may be 

 descried in the Pleistocene history of Scotland. 



1st. A period when the countiy stood as high, or greatly higher 

 than at present, with an extensive development of glaciers and 

 land-ice, which polished and striated the subjacent rocks, trans- 

 ported many of the erratic blocks, destroyed the pre-existing 

 alluvium, and left much boulder-earth in various places. 

 2nd. To this succeeded a period of submergence, when the sea 

 gradually advanced until almost the whole country was covered. 

 This was the time of the marine drift with floating ice. The 

 beds with arctic shells also belong to it ; and some of the brick- 

 clays are probably but the fine mud of the deeper parts of the 

 same sea-bottom. 

 3rd. The land emerged from the water, during which the preceding 

 drift-beds suffered much denudation, giving rise to the extensive 

 superficial accumulations of water-rolled gravel that now over- 

 spread much of the surface. This movement continued until 

 the land attained a higher position than it now has, and became 

 connected with the continent of Europe : its various islands 

 were probably also more or less in conjunction. The present 

 assemblage of animals and plants gradually migrated hither 

 from adjoining lands. Glaciers may have still formed in favour- 

 able places, but probably never regained their former extension. 

 4th. The land sank again until the sea in most places reached a 



