206 D. Milne Some — Glaciation of the Sheilunch. 



1879 (of which paper they had courteously sent to me a copy), I 

 thought it allowable, in vay annual Address as President of the 

 Edinburgh Geological Society, to express, as bearing on an important 

 question of Scotch Geology. 



Messrs. Peach and Home, not acquiescing in my criticisms, have, 

 in the article to which I refer, as they were entitled to do, given 

 explanations on some of the points noticed by me ; and I now desire 

 to say, how far I am satisfied, or not satisfied, with their explanations. 



1. On one point I am of course satisfied. I had demurred to 

 the astounding declaration in their paper, " that the land-ice which, 

 glaciated Scotland could only have come from Scandinavia" (page 

 809). 



These gentlemen explain that, "owing to an unfortunate printer's 

 error, the word Scotland in the foregoing sentence has been sub- 

 stituted for Shetland " — " an error (they add) self-evident to any 

 ordinary reader after a careful perusal of the context." 



I at once accept the explanation ; but when it is said that to any 

 ordinary reader the error was self-evident, I must be allowed to 

 reply that the context did not, and even now does not, manifest the 

 mis-print to me. 



2. The more important question is, whether there be sufficient 

 evidence in the paper to support the theory originally started by 

 Dr. Croll, and warmly advocated by his colleagues in the Survey, 

 that the Shetlands were " over-ridden " and " smothered " by a 

 Scandinavian Ice-sheet. 



(1). They state that the arrival, impact, and progress of this 

 Ice-sheet on the Islands, is indicated by numerous strics on the 

 rocks. Along the whole Eastern Seaboard of the Islands, the striae 

 show, it is said, a movement of the ice from N.N.E. or N.E. ; but 

 that, after " impinging on the Islands," and " reaching the crest of 

 the Mainland, it was deflected by the opposing high ground," " and 

 as it left the Mainland, it veered round towards the N.W. and 

 N.N.W." (page 796). This remarkable phenomenon is again 

 described thus : — " The Ice-sheet abutted on the Eastern Seaboard 

 of Shetland with a S.S.W. and S.W. trend ; and after reaching the 

 crest of the Mainland, it swung round to the N.N.W. and N.W." 

 (page 790), in order, as is afterwards explained, to "follow the path 

 of least resistance" (page 809). 



Among the places on the Eastern Seaboard, where the direction 

 of the striee is given, there is the Island of Unst, at the north end 

 of the group. The exact direction of the strige there is thus stated : — 

 " Along the Eastern Seaboard of Unst, the direction of the ice- 

 markings varies from W. to W. 20° S. From Norwick to Harolds- 

 wick, numerous striae occur on the cliff-heads, running W. to W. 

 20° S. ; some of which were found on the top of a cliff 500 feet 

 high ; while in the southern parts of the island the average trend is 

 W. 30° S." 



I stated in my Address that considerable doubt must be felt as to 

 the correctness of these statements, on account of the discordant 

 testimony of Mr. Peach, senior, who, at the special request of 



