IQ2I. No. II. THE STRAVDFLAT AND I^OSTASV. 



219 



Along the Sondmor and Romsdal coast the submerged strandfiat is 

 considerably wider and more developed, forming platforms extending 

 far out to sea. Outside the islands Fjertoft and Haroi. north-east of Åle- 

 sund, these platforms extend as much as 8 or 10 kilometres seawards from 

 the outer coast of the islands, and have depths to a great extent less than 

 10 metres below sea-level. Their surface is somewhat uneven and dis- 

 sected by channels and depressions, and their edges do not seem to be 

 very sharply defined. 



The submerged strandfiat is similar outside the coast at Hustad. 

 It is especially well developed in the region of Smolen. Froia. and the 

 Froan Islands where it extends 12 to 20 kilometres, or more, seawards 

 from the outer coast of the big islands, and has a level surface, less than 

 10 metres below sea-level, and well defined edges. It is. however, dis- 

 sected by numerous channels. This strandfiat is cut in pressed igneous 

 rocks and granites, which, however, seem to have no very great power of 

 resistance to erosion by frost. The submerged strandfiat of this region 

 has, on the whole, a greater area than the emerged strandfiat. 



Along the coast to the north-east the submerged strandfiat is well 

 developed, and its surface topography is largely similar to the one just 

 described. 



Along the coast of Helgeland the submerged strandflat is of ex- 

 ceptionally wide extent. The area of the emerged strandflat is quite small 

 in comparison. The surface of this submerged strandflat is. as a rule, 

 very level, almost perfectly horizontal, and less than 10 metres below the 

 sea-surface, largely in fact between 2 and 6 metres. Its edges are to a 

 great extent sharply defined with steeper side slopes. Where the rocks 

 are mica-schist, limestone, and weak gneiss the surface of this submerged 

 strandflat is more level and the edges more sharply defined, than where 

 the rocks are granite or other fairly resistant igneous rocks. 



In Lofoten and \'esteràlen the submerged strandflat is not broad, 

 obviously owing to the great power of resistance of the rocks to erosion, 

 and also owing to the considerable initial height of the land. The sub- 

 merged strandflat of this region has, however, as a rule a much greater 

 width than the emerged strandflat. Its depth is as a rule greater than 

 those of the submerged strandflat of Helgeland, its surface is less hori- 

 zontal, and the edges less marked. 



Along the coast to the north-east there is also a well developed sub- 

 merged strandflat at about the same depth, as far as Ringvasoi and Kvaloi. 



The three Levels of the Strandflat. 



We may thus assume that the strandflat of Norway has at least three 

 different levels: An upper level which in southern Norway is mostly be- 

 tween 30 and 40 metres above the sea (in some regions, as for instance 



