KKIinjOF NANSEN. M.-N. Kl. 



II. THEORIES OF THE GENETIC ORIGIN OF 

 THE STRANDFLAT. 



Tlie \'ie\vs as rcg'ards the genetic orijj^'in of the straiulflat liave varied 

 iiuicli, and liave chiefly been the following: 



J\ e u s c h explains the strandfiat as being a plain of marine abrasion, 

 chiefly due to wave erosion, but the general subaërial denudation, imme- 

 diately near sea level, has also been of some importance. The plain was 

 formed chiefly in Tertiary time along a but slightly dissected coast, but 

 it was also to some extent formed during "that portion of the glacial 

 period when our country was comparatively free from ice". 



E. Richter [1896] also maintained very decidedly that the strand- 

 flat was formed by wave erosion, but in interglacial time. 



J. H. L. Vogt [1900, 1907] is strongly in favour of the view that 

 the strandfiat has been formed by wave erosion along a practically un- 

 dissected coast. He thinks that in Helgeland (and northern Norway) the 

 strandfiat was cut in this manner into the massive block of land to a width 

 of about 45 kilometres, long before this land was dissected by the numerous 

 deep valleys, fjords, and channels now existing. The layer of solid rock 

 thus cut away, had a thickness of at least 400 metres along the inner zone 

 of the strandfiat, and in some regions even more. Vogt assumes that the 

 development of the strandfiat may have gone on ever since the time of 

 the Jurassic dislocation on Andoi till the beginning of the first Ice Age. 



The view that the strandfiat is a plain of marine abrasion (wave 

 erosion) has also been held by Davis [1899], Re k stad [191 2, 1915], 

 Sahl strøm [1917], D. W. Johnson [1919], and others. 



A n d r. M. Hansen [1894, 1898^ assumed that the Norwegian 

 strandfiat had been formed during the later part of the first Great Ice 

 Age, partly by wave erosion and partly by the scouring of the drifting ice 

 along the shores of the sounds. The coast had then already been dissected 

 by numerous fjords and channels, greatly increasing the line of attack. 

 The mode of formation of the strandfiat was supposed to be practically 

 the same as that of the shore-lines. The broad strandfiats are simply 

 several shore-lines which have met and united, advancing from different 

 sides of the islands and peninsulas. 



