1921. No. II. THE STRAXDFLAT AND ISOSTASY. 29 



morph.c structures mainly, represented l)y numerous schists, gneisses, and 

 quartzites. "Because of its low lying attitude and meager rainfall it 

 has been little dissected." 



Pushing does not give the height above sea-level of the inner margin 

 of the plane, but it might be inferred that it cannot be much over 70 or 80 

 metres; and the plane dips gently seawards to the low, flat shore. 



It is conceivable that, in a region with very meager rainfall, and con- 

 sequent slow subaërial denudation, the wave erosion may, in the length of 

 time, be able to develop sharply defined planes backed by oversteepened 

 sea walls. But in regions with a more abundant rainfall, the subaërial 

 denudation will work faster than the wave erosion. During the long time 

 which the latter would require for the development of a broad plain of 

 marine abrasion, the subaërial denudation would certainly denude the land 

 surface much more, and it would wear down the sea wall (the cliff), and 

 give it a gentle slope. If the plain of marine abrasion be elevated (by 

 isostacy) above sea-level, its surface would gradually be more or less dis- 

 sected by the subaërial denudation, and after some time there may be no 

 very sharp boundary between the marine plain and the more undulating 

 surface inland, especially as the whole land would gradually be elevated, 

 by isostatic movement, at about the same rate as it was denudet, and n:-arly 

 the same amount. 



Hence, as a rule, we will find no typical and sharply defined strandfiat 

 in regions with an active subaërial denudation, unless there have been 

 especially favourable conditions for its development, like those prevailing 

 in regions exposed to severe climates. 



After having had an opportunity of studying the process of marine 

 denudation and its effects more closely, especially in Spitsbergen, I have 

 modified somewhat my earlier views [1904, 1905] as to the manner in 

 which the strandfiat has been developed (mentioned on pp. 5 f.). I have been 

 lead to the conclusion that the wave erosion has been of but little direct 

 importance for the planing of the strandfiat of northern regions, compared 

 with the erosion effected by frost in and just above the shore-line, wdiich 

 process I have found to be even much more effective in an arctic climate, 

 than I formerly believed (cf. above p. 5). 



As the general expression 'marine denudation' is bv most writers 

 combined with wave erosion, I prefer to use the expression shore erosion 

 by frost for this special form of marine denudation. 



When sea-water freezes (at — 1° to — i.9°C.) it does not expand so 

 suddenly in the moment it is transformed into ice, as fresh-water does 

 at o" C. But at sinking temperature the ice of sea-water goes on expanding 

 gradually [cf. O. Pettersson, 1883]. According to my observations, this 

 continues as long as the sea-ice holds in its pores liquid brine which is 

 gradually transformed into ice. New sea-water ice is also soft, porous, 



