no /. G. ANDERSSON 



Leurs versants sont couverts d'enormes eboulis des memes gres et quartz- 

 ites, rendant tres possible I'acces du sommet. Les amoncellements de gres 

 d'un blanc de neige et de quartzites qui descendent dans les vallees laterales, 

 off rent un aspect tres original; de loin ces trainees, de pierres ressemblent 

 de vrais cours d'eau, tant le caractere de leurs sinuosites rappelle les veritables 

 torrents. 



One of these Ural stone-rivers is figured in Ratsel, Die Erde, 

 Vol. I, p. 479, this figure showing a complete resemblance to the 

 Falkland stone-runs, only with the exception that the Ural stone- 

 river is bordered, not by a grass steppe, but by pine forest. Accord- 

 ing to a communication given by Hogbom, the region of the Ural 

 stone-rivers lies outside the area of earlier glaciation. Nothing is 

 then more natural than to explain also these formations as an extra- 

 marginal equivalent to the ice-sheet. 



To this account of fossil occurrences of solifluction we must 

 add that Sernander in the mountain region of Harjedalen has found 

 evidence of a considerably larger extent of the flowing soil in a by- 

 gone past of the postglacial epoch. ^ 



The study of the traces of solifluction in earlier times is highly 

 attractive, and of great importance for the understanding of the 

 climate of the past and for the explanation of the chronology of the 

 Quarternary period in extra-glacial regions. But these are problems 

 which lie outside the scope of this article, and which, moreover, 

 I will treat in detail in a paper on the geographical development 

 of the Falkland Islands. 



CONCLUSIONS 



From the evidence given in the preceding pages it is easy to 

 recognize the climatic features which form the optimum of the 

 solifluction. In the polar and subpolar regions, where the ground 

 is not covered with ice, we find this process working with more or 

 less intensity almost everywhere, and in the same manner, the 

 alpine tracts of lower latitudes are favorable for the develop- 

 ment of this phenomenon. In these regions, characterized by a 

 "subglacial" chmate with heavy deposits of winter snow melting 

 in summer, solifluction is a chief agent of destruction. The 

 unceasing succession, summer after summer, of mud-streams and 



^Geologiska Foreningens Forhandlingar, 1905, pp. 42-84. 



