450 D. Milne Some — Glaciation of the Shetlands. 



What is IMessrs. Peach and Home's reply ? "The deflection along 

 the eastern seaboard, suggested by Mr. Milne Home, is what we 

 believe to have been the case." " But eventually the pressvire of the 

 advancing mass was sufficient to compel it to override even the 

 highest hills ; and on reaching the mainland, having surmounted the 

 resisting high ground, it naturally (sic) veered round to the west " 

 (p. 369). 



But towards what direction would "the advancing mass," coming 

 along the eastern seaboard, be pressing? What was there to cause 

 it to leave the " path of least resistance " it had taken, and swing 

 round in order to •' surmount the high ground of the mainland " ? 



The pressure of the mighty mass, advancing from the N.E., or 

 rather from N. by E., along the eastern seaboard, would retain it in 

 that course, and cause it to avoid any traverse of the islands. 



Messrs. Peach and Home, seeing this, call in the aid of " Scotch 

 ice moving in a N.W. direction, which (they say) must have had 

 a considerable influence in deflecting the Scandinavian mer de glace 

 to the N.W." (p. 370). 



Where this Scotch ice came from, is not explained ; — and of its 

 existence, not the slightest evidence is given. But it is not in the 

 least likelj', that any paltry mass of ice generated in the north of 

 Scotland could, by passing into the North Sea, and encountering the 

 Scandinavian monster moving along the Shetland seaboard, have 

 power to turn it, and force it into another course at right angles 

 to its previous course. 



II. The evidence on which Messrs. Peach and Home seek to show 

 that their mer de glace was again deflected, and made to cross the 

 islands in a N.W. direction, consists of boulders and roch striations. 



1. In regard to boulders, many of which (it was said) were 

 " carried from the lower to the higher levels ; — indeed carried to the 

 highest hills," in virtue of "the westerly movement of the great mer 

 de glace " (p. 804), I asked : — 



(1). Whether "the effect of such an agency would not rather be 

 to sweep off from ridge and hill-top every particle of rubbish, and 

 leave no boulders on them ? " (p. 211). 



To this inquiry, Messrs. Peach and Home reply, "that some of the 

 boulders were borne forward in the ground moraine; while others 

 became fixed in the lower portion of the ice-sheet, and were likewise 

 carried forward by the advancing mass. As the ice melted back- 

 wards, the rocks and angular dehris were stranded at the localities 

 where we now find them, except where displaced by later move- 

 ments " (p. 372). 



Boulders can no doubt be "carried forward" by a mass of ice; but 

 if left by the ice, when either "advancing" or "melting backwards," 

 it would not be on ridges or hill-tops, but in the valleys through or 

 over which the ice passed. 



But the Shetland group consists of islands, separated bj'^ sea 

 sounds, some of them many fathoms deep and many miles wide. 

 Across these sounds, as well as the islands, the mer de glace is said 

 to have passed ; and in doing so, any boulders carried by it must 



