1 92 1. No. 1 1. 



THE STRAXDFLAT AND ISOSTASY. 



Fig. 156. The level surface of the platform in Lake Valley, with a terrace of big stones at 

 the foot of the steep mountain. August 10, 1912. [From Nansen, 1920]. 



of the Strandfiat. Its rocks are also scoured and rounded, e. g. at \"er- 

 leegen Hook, and striæ have been observed, as mentioned bv Peach. 



This strandfiat niust, therefore, have been planed to its present levels 

 after the Great Ice Age, or Ages, and before the last great advance of 

 the glaciers of Spitsbergen. 



In Chapt. \'I (pp. 47f.) I have pointed out that the strandfiat of 

 Norway has obviously been developed during periods when the land crust 

 had attained its natural level of ei|uilibriuni, anrl the shore-line remained 

 stable during a long time. i. c. during periods when the land was not 

 depressed by the weight of any ice-caps. At the same time there must 

 have been a severe climate favouring the shore erosion bv frost. I there- 

 fore consider it probable that the Norwegian strandfiat has to a great 

 extent been formed during periods with a severe climate preceding each 

 glacial period, and before the land had been depressed by the inland ice. 



In Spitsbergen the conditions are different. The land is still covered 

 with glaciers to a very great extent, and we cannot say what the natural 

 level of ef|uilil:)rium of the crust may actually be. At the same time the 

 climate of that region is so severe that probably, even during warmer 

 interglacial periods, it was sufficiently cold for an active shore erosion 

 by frost. 



Nevertheless it is a striking fact that the emerged as well as the 

 submerged strandfiat of Spitsbergen have levels that are very similar 

 to those of the Norwegian strandfiat, and we may assume that they 

 indicate levels of an approximate natural equilibrium of the crust in 

 this region. 



I imagine that the Spitsbergen strandfiat was planed to its present 

 levels during interglacial periods when the shores were not covered by 

 glaciers and the ice covering of the land was similar to what it is now. 



