268 A. J. Julces-Broione — The Formation of ' Till.' 



these regions. The first of these is the strip of border-land which, 

 intervenes between the inland ice and the sea-margin, and which is 

 the habitable part of the country ; over its surface are scattered 

 occasional ponds and lakelets, it is clothed in summer time with a 

 certain amount of vegetation, and is frequented by many Arctic 

 animals. The second feature consists in the frequent occurrence of 

 clay banks along the shore, and especiallj'- in fi'ont of some of the 

 larger glaciers. Now have we not in these phenomena some indi- 

 cation of the conditions under which the so-called interglacial beds 

 and the so-called Till were severally formed ? 



Prof. Nordenskiold (p. 409) describes a raised plateau of marine 

 glacial clay, now forming part of this border-land, and covered with 

 a scanty vegetation ; suppose this land surface to be gradually sub- 

 merged again, so that the sea might once more wash against the 

 face of the inland ice, what succession of deposits should we then 

 expect to be produced ? would not the land-surface with its oc- 

 casional fresh-water beds be covered by more or less stratified 

 marine deposits passing up into unfossiliferous glacial clay, in which 

 erratics would be rare or frequent according to the production of 

 icebergs from the ice- wall ? and would not the whole series be very 

 similar to that near Woodhill Quarry in Ayrshire, as described by 

 Dr. Geikie at pp. 160-2 of his "Great Ice Age"? The succession of 

 changes which he considers to be indicated by the evidence there 

 found are given at p. 174, and these are exactly what we have just 

 supposed as taking place in Greenland, only that the periods of time 

 would be comparatively short, the changes of climate less extreme, 

 and the upper glacial clay would not be a moraine profonde. 



In a note at p. 185 concerning the similar succession of beds in 

 Lewis, Dr. Geikie says : — " I thought the beds between the two 

 Tills or Boulder-clays might indicate merely a temporary retreat of 

 the ice during some exceptionally mild years, but subsequent and 

 more detailed observations in the island have satisfied me that the 

 appearances presented by the Drift cannot be thus explained." I 

 think I am not the only reader of this Magazine who would wish to 

 be similarly satisfied. The members of the Scottish Survey ai'e, I 

 believe, unanimous in accepting the moraine profonde theory ; those 

 of the English Survey, who are now mapping the Drifts of East 

 Anglia, are mostly inclined to the hypothesis of the marine or sub- 

 littoral formation of Boulder-clay. 



It is worthy of note that these two theories lead to entirely 

 opposite conclusions regarding the periods of elevation and sub- 

 mergence. According to one set of observers the land is high and 

 elevated at the very same time when the others believe it to have 

 been low or submerged. 



Must we ever thus agree to differ, and is there no possibility of a 

 middle course being found, in which we may sail safely between the 

 dangers of icebergs on the one hand and ground moraines on the 

 other ? I for one am quite willing to be partially if not entirely 

 converted, but I am still in the sea of difficulties. 



If Dr. Geikie favours me with any reply to the above remarks, 



