1 92 1. No. 1 1. 



THE STRANDFLAT AND ISOSTASY. 



Fig. 112. The mountain Tonningen, seen trom the north-western shore ot Laugen Lake, which 

 is seen in the foreground. (Photograph bj' J. Schetelig, 1909). 



schists and pressed schistose igneous rocks, wliich were fairly liable to 

 erosion by subaërial denudation as well as l)v marine denudation. 



On the other hand the erosion, the subaërial as well as the marine 

 erosion, has been much more favoured by a severer climate in this northerly 

 latitude than it was along the coast further south. The severe and frequent 

 frosts of a beginning glacial period would commence much earlier here and 

 last much longer than along the southern coast of Norway. The subaërial 

 denudation would be much increased by the disintegrating effect of the 

 frosts, and the shore erosion (by frost), assisted by the stormy sea, would 

 become very vigorous, planing down the low land, which was already 

 dissected into numerous small islands during previous glacial periods. 



Finally the probability is that these islands out in the sea, were 

 covered much later by the inland ice than the coast of the mainland, and 

 they were therefore exposed to the destructive forces of a glacial climate, 

 combined with the attack of the sea, during a much longer period than 

 other parts of the coast. 



It seems to me that these are reasons giving a satisfactory explanation 

 of the occvirrence of a very wide and fully developed strandfiat in this 

 region, as well as along the coast of Nordland to the north, as we shall 

 see later. 



It has been maintained, l)y Ahlmann and others, that the glacial 

 erosion might have helped to plane the strandfiat. Such a view seems 

 contrailictory to what ma\' now be considered as an esta])lished fact, namely 

 that it is greatlv the glacial erosion which has dissected the coast into its 

 thousands of islanrls and skerries. If, for instance, we look at the map 

 Fig. 107, it woulrl indeed l)e rlifficult to unrlcrstand why the glacial erosion 

 should lia\X' helped to plane the surface of Smalen and Froia while it has 

 dissected the surroundinsj- lan'l into those swarms of islets, often with 



