36 



KRIUTJOK NANSr.N. 



M.-N. Kl. 



Fig. 17. Shore-ledge 8 metres broad cut in argilaceous shist on the Fornebo Peninsula. 



The actual occurrence of such shore-ledges, recently eroded by frost 

 in solid rock and at present sea-level along- shores where a considerable 

 wave action has been working simultaneously, as is the case in Kvænangen 

 Fjord exposed to the stormy Loppen Sea, is a convincing evidence that, 

 Avhere the necessary conditions are present, the shore-erosion by frost is 

 much more effective than the wave erosion, and it is able to cut shore- 

 benches in solid rock in a much shorter time. 



It might be objected that the mountain sides of Kvænangen Fjord, 

 where Vogt's ledges have been cut, are so very steep with so deep water 

 just outside (a depth of 22 metres only 4 metres outside the shore) that 

 the wave erosion would, in any case, have very little effect on such a 

 nearly vertical rock wall. But the fact is, as Aogt points out, that the 

 loose stones as well as the projecting solid rocks on the rough surface of 

 the ledges are angular, and show no appreciable traces of having been 

 rounded by the waves. While the disintegrating effect of the frost has 

 been able to cut these ledges 8 and 12 metres broad into the steep mountain 

 wall, the wave erosion has not even been able to produce any appreciable 

 effect upon the outer edge of these ledges. The wave action has, however, 

 obviously been of importance by helping to carry away the débris. 



Similar shore-ledges, formed by shore-erosion by frost, also occur in 

 more southern latitudes. Along the shore outside my house on the Fornebo 

 Peninsula (at Lysaker), in the inner end of Christiania Fjord, relatively 



