r^S FRiin.ioi- NANSKv. M.-N. Kl. 



Fig. 115. Cliart ol tlu- Hysvær Plateau, northwest of Vega and Søla islands, based upon 

 the Chart No. 54 publislicd by „Norges geografiske Opmåling". The figures in the sea 

 indicate the tl(|)»lis in nurtres below low-water level, which is about 1.5 metres below 



mean water-level. 



rletailefl charts of the coast of Norway. It is given here as a characteristic 

 illustration of the detailed surface relief of these submerged plateaus. The 

 figures give the depths in metres below lowest water-le\ol, which is alxjut 

 1.5 metre below mean water-level. Isobaths are drawn with flotted lines 

 for 5 metres, with broken lines for lO metres, with thin lines for 20 metres, 

 and with thick lines for 50, 100, anrl 130 metres of depth below lowest 

 water-level. 



The isobath for 10 metres follows as a rule very closely and at a 

 very short distance the isobath for 20 metres, so that the area bounded 

 bv the latter contour line is not substantially larger than that bounded 

 by the 10 metres line. The isobath for 5 metres demonstrates that the 

 greater part of the surface of the plateau is even less than 5 metres below 

 lowest water-level, and over great areas the de])ths are between 0.5 and 



3 metres. The general horizontal level of this plateau may be said to be 

 between 2 and 7 metres below mean sea-level, and in its nortlieastern part 

 near the islands of Hysvær, it is almost in the sea-surface. 



Fig. 116 gives a profile across this plateau along the broken line in 

 Fig. 115, passing across Sola Island northwestwards to Skjærvær and 

 thence seawarrls. This profile demonstrates the remarkably horizontal 

 evenness of the plane of this plateau, in which the channels and hollows 

 form sharply defined depressions with well marked edges, mostly at 3 to 



4 metres below mean sea-level. 



The even surface of this sul)merged plateau has olniously much 

 resemblance to the even planes of the emerged strandfiat, c. g. on Dønna 

 and Heroi, described by Sahlstrom and mentioned later. 



The other submerged plateaus shown in Fig. 113, have a similar 

 surface relief, but their outer parts in the northern and southern regions 

 of this map are somewhat more broken and irregular. The Hysvær Plateau 

 has a width of about 15 kilometres, and the other submerged plateaus 

 have a similar extent. 



Several writers, the present one included, have stated that the edge 

 of the siihiiicrgcd strandfiat of Helgeland is at 20, 30 or 40 metres below 

 sea-level. This is hardly correct and is apt to give an entirely wrong 

 impression that the plane of the strandfiat slopes to such a low level. 

 As we have just seen the almost perfectly horizontal plane of the sub- 

 merged straiulflat lies very near present sea-level, and. as Fig. 115 demon- 

 strates, the edge of this plane is sharply defined at depths of less than 

 10 metres below the water surface. 



