A. J. Jukes-Broicne — The Formation of ' Till.'' 267 



is formed, and rocks polislied and striated by glacier-ice, is so well 

 known from observations in the Alps and elsewhere, that I think 

 Prof. Milne himself cannot deny its capability of producing such 

 effects." The italics are mine. 



Prof. Milne will doubtless state his own views more fully, and I 

 think he may very fairly claim to have the evidence of Till being 

 formed under Alpine glaciers set before the readers of this Magazine. 



In Dr. Geikie's " Great Ice Age," I only find mention of the stones 

 frozen into the bottom of glacier-ice (p. 40), and a theoretical descrip- 

 tion of the supposed formation of ground-moraine under the Scottish 

 ice-sheet (p. 68). I think, therefore, that many geologists would be 

 glad to have an authentic description of the actual formation of 

 moraine profonde at the present day, either in Switzerland, Norway or 

 Greenland. Have the original statements of Agassiz and Charpen- 

 tier ever been confirmed, and are the facts such as would warrant 

 the creation of such a monster as modern glacialists have constructed 

 out of their moraine profonde ? 



One good observer at any rate replies in the negative ; speaking 

 of some retreating Swiss glaciers, Prof. Bonney says,^ "In no case 

 have I been able to find any deposit resembling Till or Boulder- 

 clay ; .... by availing myself of crevasses, etc., I have made my 

 way occasionally for some little distance beneath the ice. Nothing 

 has been seen but bare rock with now and then a film of mud or a 

 passing stone." 



Dr. Geikie, however, is quite satisfied that no considerable deposit 

 accumulates under Alpine glaciers, and he says, " A mountain glacier 

 is one thing — a glacier extending far into the low grounds beyond 

 the mountains .... is another and very different thing." But is 

 the difference more than one of degree ? their behaviour, ceteris 

 paribus, must surely be the same. Dr. Geikie maintains that the 

 moraine profonde will only be formed in any quantity when the 

 glacier reaches the plains beyond the mountains, but the vipholders 

 of the glacier erosion theory say that a lake is likely to be formed 

 where a glacier debouches on to level ground. Dr. Geikie has, 

 of course, thought over this difficulty, and can doubtless explain 

 how he reconciles the two views, if indeed he accepts the latter. 



Again, the Greenland glaciers are of large size, but can he point to 

 the existence of griind-moraine beneath them ? Those descriptions 

 of Greenland ice which I have had an opportunity of reading seem 

 rather to negative than confirm the supposition of its existence. An 

 excellent account was contributed to this Magazine* by Professor 

 Nordenskiold, who distinctly says that when the ice retires it gives 

 rise to a slope covered with boulders, not to a moraine. Again he 

 speaks of the smoothed, scratched and grooved rocks, showing that 

 the fiords have been widened and cleansed from earth, gravel-beds 

 and mountain detritus by the operation of glaciers {loc. cit. p. 365). 



There are, however, two peculiar features which are observable 

 along the coast, and have been described by most travellers in 



1 Geological Magazine, Dec. II. Vol. III. p. 197. 



2 Geological Magazine for 1871, Vol. IX. 



