134 



FRIATJOF NANSEN. M.-N. Kl. 



SO \vcll-flcvcl(jpc'l in tliis iiortlicni region, aii'l stil! Ijctler further iiorlli 

 in Tromsø Fylke and I'"inniark, wliile tliey are liardly seen alonj,^ the 

 coasts of southern Nc^rway. 



On the other hand the rocks forniin;^ ihc oiUcrniost CÆSt of Hclf^elanrl 

 are on the whole less resistant to erosion than the rocks of the Romsdal 

 and Sondmore region and also on the whole less resistant than the igneous 

 rocks of T.ofoten and Vesterålen. It is furthermore probable that the 

 initial outer ctvist land 'of the Helgeland region was comj^aratively low. 

 and that no great quantity of rock had to be planed down for the formation 

 of the strandfiat, after this land, consisting of the low outer folding ridges 

 of the great Caledonian mountain foUling of Northern Norway, had been 

 dissected into thousands of islands bv tlie glacial erosion. 



The stage of development of the strandfiat varies somewhat in the 

 different parts of the coast. In some regions, c. g. in Heroi, Donna, and 

 Solvær, the emerged surface is (juite unusually level, whilst in other region?, 

 c. g. on the \'ikten islands, in the region of Tcjrghatten, &c., the surface is 

 undulating with more hills and ridges rising to different heights above the 

 plane of thé strand flat. This depends naturally on the degree of maturity 

 to which the strandfiat lias been developed. In regions with less resistant 

 rocks, or where the land was more dissected into smaller islands, and 

 where there was much less rock to be planed down, the strandfiat was 

 sooner developed to full maturity than in regions where the conditions 

 were less favourable. Along a coast where the conditions differ much 

 in this respect we may therefore expect to find the strandfiat in all stages 

 of maturity. 



It has to be admitted that if one consid:rs the stra-.dfiat to have been 

 formed solely by wave erosion, it might be difficult to understand how 

 any strandfiat at all could have been formed in regions where numerous 

 hills and ridges are still rising above the plane of th? strandfiat, with 

 no great distance between them. One would expect that the waves would 

 have had to wear down the hills on the seaward side first before they 

 could obtain the necessary force to erode a strandfiat further inland. 



But in a severe climate the effecti\'e shore erosion l)y frost works 

 simultaneously along all shore-lines, on the outer as well as the inner sides 

 of the islands and peninsulas, and in all small creeks and bays. The islands 

 will thus be attacked from all sides, and by the joint action of subaërial 

 denudation, the shore erosion by frost, and the waves carrying away the 

 débris, the strandfiat may gradually be developed to different stages of 

 maturity in the whole indented and dissected coastal region at the same 

 time. 



Fig. 1 13. gives a map of the strandfiat along the coast of Helgeland 

 from Bindal Fjord to Donna Island. As material for the drawing of 

 this map, I ha\e used the excellent detailed charts in the scale of i : 50.000, 

 and the maps ("Gradavdelingskarter") in the scale of i : 100,000, published 



