192 1. No. II. THE STRAXDFLAT AND ISOSTASV. 49 



The Height of the Norwegian Strandflat. 



Several writers, like J. H. L. \ ogt, Thorolt \ ogt, and A. G. Høgbom, 

 make the height of the inner margin of the Norwegian strandflat, at the 

 foot of the steep mountains, especially in Helgeland and Lofoten, to be 

 near 40 metres above sea-level, Oxaal says between 40 and 50 mstres, 

 perhaps nearest the former height, while H. Reusch and Andr. M. Hansen 

 put it at 100 or even 120 metres. The reason why the latter writers have 

 got such great heights is obviously that they have taken the benches of 

 raised beaches as belonging to the strandflat. 



As was pointed out on p. 42, there is, however, this striking difference 

 between the strandflat and the raised beaches, that the planes of the former 

 are very nearly liorizontal and have obviously been developed during times 

 with a more or less stable sea-level, while the raised beaches are tilted and 

 have been formed during periods of submergence of the land, when the 

 shore-line was staying at temporary levels for relatively short periods. 

 It ought therefore to be sharply distinguished between the two kinds of 

 formation, although they are formed more or less by the same process of 

 erosion; and may often lie nearly at the same levels. 



But even if we stick to the planes of the real strandflat it may be 

 difficult to determine the exact height of their upper limit because, on the 

 one hand, this limit between the strandflat and the steep mountain side is 

 not often very sharply marked, as the upper planes of the strandflat are 

 old formations, which have been much modified and dissected by later 

 glacial erosion, and on the other hand, the level of the shore-line has not 

 remained quite stable during the development of the strandflat, and its 

 planes are obviously formed at somewhat different levels. Amongst other 

 things it may then to some extent depend on the resistance of the rocks 

 which plane has become most conspicuous. 



Nevertheless there is a fair agreement between the estimations of 

 most writers of the height of the upper limit of the strandflat, but at the 

 same time distinct lower planes of the emerged strandflat have also been 

 described. We shall return to this subject after our investigations of the 

 strandflat have been described. We will then also have to consider another 

 question: Why it is that these nearly horizontal levels of the strandflat are 

 now raised above present sea-level? 



The partial Absence of a Strandflat along some Parts 

 of the Norwegian Coast. 



A difficult question of much interest is: Why there are so great dif- 

 ferences in the development of the strandflat along the various parts of 

 the Norwegian coast? 



While the high and steep west coast of Norway has a well developed 

 and broad strandflat, in some places nearly 40 kilometres broad, there are, 



Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 11. 4 



