ig21. No. II. THE STRANDFLAT AND ISOSTASV. 7 



when, however, the raised beaches were formed. A characteristic diffe- 

 rence between the strandfiat and the raised beaches is that, the former is 

 horizontal, and indicates stable levels which the land has had during long 

 periods, while the latter are tilting and indicate the levels of the shore-line 

 during a temporary submergence of the land. 



As being of importance for the development of the strandfiat it was 

 also pointed out that by each advance of the glaciers of the glacial periods 

 the waste was carried away seawards from the land and the shores, leaving 

 bare rock surfaces for attack when the glaciers retreated. 



I still hold similar views on most points regarding the nature and 

 formation of the strandfiat, as I did at that time; but I now am of the 

 opinion that the shore-erosion by frost is of even much greater importance 

 for the marine denudation of the strandfiat than I thought then. 



Nearly the same views regarding the nature and genetic origin of the 

 strandfiat, as put forth in my report, have also been held by T h o r o 1 f 

 Vogt [1912, 1914], Otto Norden skjold [1912, 1914], A. G. 

 Hogbom [1913], and others. In his admirable paper, Hogbom proves, 

 by numerous convincing evidences, the untenability of the above mentioned 

 tectonic theory of De Geer and Sederholm, explaining the strandfiat as 

 formed by dislocations. He points out that the coast land must have been 

 dissected by the fjords before the strandfiat was developed, and had been 

 so much lowered by subaërial denudation that there was not very much 

 left for the marine abrasion to cut away in order to form the strandfiat. 

 He thinks that this last quantity of rock may thus have been at most 

 ten per cent of the quantity calculated by J- H. L. \'ogt as having been 

 cut away by marine abrasion. I would be inclined to reduce even this 

 figure considerably. 



In his recent publication "Geomorphological studies in Norway" 

 [1919] Hans W:s o n A h 1 m a n n has discussed the nature and genetic 

 origin of the Norwegian strandfiat. As his views in this respect differ from 

 those of previous writers I shall have to mention them at some length ^. 



Ahlmann arrives at the somewhat startling conclusion that a Nor- 

 wegian strandfiat (or "coastal plain" as he calls it) does not really exist. 

 In the first part of his paper he assures us that the formation, previously 

 called so, has nothing to do with marine denudation. It is a base-levelled 

 plain formed solely by subaërial denudation, in some places assisted by 

 glacial erosion. He therefore thinks that the name of "coastal plain", or 

 strandfiat, for this formation is inadequate, and proposes to call it "the 

 distal base-levelled plain". 



^ Just as this manuscript is going to press I have received from Prof. A. G. H g - 

 borna paper [1920] discussing Ahlmann's views. Hogbom's points are to a great 

 extent the same as mine, but he has also mentioned some other sides of the subject 

 which I have not paid attention to. 



