I92I. No. II. THE STRAXDFLAT AND ISOSTASY. 5 



Hansen considers that the glacial erosion has also been of much im- 

 portance, particularly lor the denudation of the low level surface of the 

 skerries. He also pointed out that during the time mentioned, when the 

 margin of the first inland ice still remained in the fjords, the climate 

 greatlv favoured subaërial erosion. 



A m u n d H e 1 1 a n d, and later F. X u s s b a u m [1909], maintained 

 that the strandfiat and the low skerries have been formed by the erosion 

 of the inland ice, advancing over the outer coast. 



A view different from most others is held by Gerard de Geer 

 [191 2] who considers dislocations to have been of great importance for 

 the formation of the strandfiat. This theory has been carried still further 

 by J. J. S e d e r h o 1 m [1913] who sees dislocations everywhere along the 

 inner margin of all shore-planes, and he tries to explain the 'stacks', sur- 

 mounting the plane of the strandfiat, as horsts bounded by numerous lines 

 of dislocations, in a most artificial and complicated manner. But strand- 

 flats do with certainty occur in many regions where there are no traces 

 of dislocations near their inner margin, and Hogbom [1913] has in 

 several places in Nordland been able to trace conspicuous lavers, with 

 gentle seaward dip. from the mountain slopes and on the sharply defined 

 plane of the strandfiat without any l^reak, which proves finally that the 

 formation of a strandfiat is not conditioned by dislocations. On the other 

 hand, investigations of Norwegian geolists have proved that dislocations 

 may often occur within the region of the Norwegian strandfiat, without 

 showing any relation to its limitation, or to the bosder lines of the stacks 

 On the contrary the plane of the strandfiat often continues across the lines 

 of dislocation without a break. 



By bringing weaker rocks in the shore-region in level with more 

 resistant rocks further inland, dislocations may naturally fascilitate the 

 formation of sharply defined shore-planes, but thev cannot form them. 



In the report [1904] mentioned above, and in a later paper [1905], 

 the present writer maintained that the Norwegian strandfiat had been 

 formed by the joint action of subaërial denudation and marine denudation. 

 after the time when the coast had been dissected by the numerous fjords 

 and channels, which now split it up into its innumerable peninsulas and 

 islands. The subaërial denudation was supposed to have been of the 

 greatest importance for the denudation of the coast land, while the marine 

 denudation had been important for the levelling of the strandfiat. During 

 the glacial periods the subaërial denudation of the coast land was essen- 

 tially increased by the disintegrating effect of the frost on land. The 

 marine denudation was due to wave erosion and also to the disintegrating 

 effect of frost on the shore that was wetted by tide and waves. The 

 transport of matter by ice, formed on the beach, was also of some im- 

 portance. 



