686 MR DAVID MILNE HOME ON THE BOULDER-CLAY OF EUROPE. 



elevation as belonging to glacial marine deposits. But when we consider their 

 continuity with the shell-bearing strata,* their regular smoothly sloping outline, 

 and add to this the travelled boulders and masses of rock on the summits of hills 

 and ridges 2300 feet high, it seems impossible to resist the conclusion that the 

 whole is of marine origin, and due to the operation of one set of causes extending 

 over a definite period." f 



The conclusion which Professor Ramsay drew from these phenomena was, 

 " that the blocks of stone that now strew our continents and islands were chiefly 

 dropped by the same agency— icebergs — that is now sowing the Western Atlantic 

 with earth and boulders derived from the mountains and coasts of Greenland, 

 where glaciers descend to the sea." % 



There is another fact connected with the position of boulders which has often 

 arrested my attention. They are more frequently found in clusters, at or near 

 the tops of hills of moderate height, than anywhere else. On the hill of Croy, 

 near Kilsyth, and on several hills to the west of Dunfermline, examples occur. 

 Almost all the very large boulders, which are known to me, are situated near 

 rising ground, and on the east side of it — as in the case of the Clochodrick stone 

 in Renfrewshire, the great conglomerate boulder near Doune, the Carlin stone 

 in Dunmore Park, and the Auld Wives 1 Lift, near Milngavie.§ 



Floating ice would ground most frequently on islets or shallow places, and 

 discharge its cargo there on melting. Glaciers occupying chiefly the lowest parts 

 of a valley would discharge their cargoes at the bottom. Therefore if boulders, 

 either singly or in clusters, most frequently occupy crests or ridges of hills, they 

 afford evidence more of icebergs than of glaciers. 



(5.) There is, however, one phenomenon of a perplexing kind, which I admit 

 cannot be easily explained by either of the two theories. I allude to the boulders 

 whose present position has been ascertained to be higher than that of the parent 

 rock. Such cases have been made out in the Isle of Man, Cumberland, and 

 Roxburghshire. If floating ice will not explain these cases, still less will land 

 ice, which, being moved by gravitation, must carry everything to a lower level. 

 On the other hand, instances are on record of stones and gravel being raised to a 

 higher level by means of floating ice, Sir Charles Lyell states, that on the 

 coast of Norway sheets of ice with pebbles and moderately-sized boulders have, 

 during a storm, been known to be driven up fully 50 feet above the sea-level. It 



* Professor Ramsay mentions (p. 96), that sea-shells were found by him at a height of 1300 

 feet above the sea, " two miles west of Snowdon, on a sloping plain of drift charged with erratic 

 blocks, one of which, of great size, is known as Maen-bras, or the large stone." 



f Proceed. Lond. Geolog. Society, vol. viii. p. 373. 



t Anc. Gl. of Wales, p. 92. 



§ De Luc (as quoted by Sir James Hall, Ed. R. S. Tr. vol. vii. p. 160) says, " that the granitic 

 blocks lying in the district between Berlin and the Baltic, occur frequently, and almost constantly, 

 in very numerous assemblages, upon the summits of the sandy hills with which that country is 

 interspersed, whilst none are to be met with in the intervening valleys." 



