146 FRIDTJOF NANSFN. M.-.\. Kl. 



will ,L;i\i' an idea of \\liii-li lici^^lils ami dcplli^ prcrlomiiiatc on llic slrand- 

 flal, liut cainiot as a rule \n- of uiucli \;iluc for finding'- the indicatifjns of 

 its orij^inal, ncarh' lioii/ontal lc\( Is or planes. In cxceiAional cases where 

 the contours run more or less concentrically and parallel lo each other, 

 it nia\' ,L;ive tairh satisfactory results, i'.ut where, as in nifjst cases, the 

 planes of the stranrlflat are rjissectcfl hy numerous channels and depres- 

 sions of varvini^' depths, and where only a part, and perhaps even a 

 conii)arati\ely small part, of the area of the strandflal actually indicates 

 its plane or planes, altliouj.(h these may he extended over ridges a{jproaching- 

 tlie outer Q(]^c (cf. the Træna Plateau, Fig". 114), there Oxaal's methfjd 

 will i^i\e results entirely misleadin«,^ for the deternnnat ion of these planes 

 and their lieit^hts. The prohahility is tliat it will generally give a more 

 or less graduallN' slojiing profile of the strandfiat with no distinct breaks, 

 and wdiere the ])lancs disappear more or less. 



From his computations of the kind mentioned above, Oxaal draws 

 the conclusion that the outer edge of the submerged strandfiat of the 

 Træna Plateau is at 30 to 32 metres below sea-level. This is hardly 

 correct, and the actual e(]ge of the original plane of the submerged strand- 

 flat is probably nearer the water surface (cf. Fig. 114). But its depth is 

 difficult to determine with accuracy along the outer side of this plateau, 

 as there is no sharply marked break between the plane of the submerged 

 strandfiat and the slope of the sea bottom outside, which slopes gently 

 towards the surface of the continental shelf. 



In this respect there is a striking difference between the outer edge 

 of the strandfiat in this region, and the sharply defined edge of the almost 

 perfectly horizontal plane of the submerged strandfiat to the south, in the 

 region of Vega (see Fig. 113). We have seen that in the latter region the 

 extremely level surface of the extensive submerged plateau stands only 

 some few metres below- the sea surface (see Fig. 115) and extends very 

 nearly to the isobath of 50 metres, which is often quite close to the isobath 

 of 100 metres, there being a sharply marked edge at less than 10 metres 

 (or near 5 metres) below mean sea-level, and a distinct l^reak between the 

 horizontal plane and the slope of the sea bottom outside.. 



But the surface of the submerged Træna Plateau is much more 

 irregular, with greater and more varying depths, and especially on its 

 outer side there is often a considerable distance between the very irregular 

 isobath of 25 metres and that of 50 metres, and the latter is largely more 

 distant from the isobath of 100 metres than from the islands (see 

 Fig. 114). 



Along the eastern or northeastern side of the Træna Plateau, at 

 Selvær and northeast of Dorvær, it is different. The isobaths of 2^, 50, 

 100, 150, 200, and 250 metres are there closer together (see Fig. 114), 

 and the surface of the submerged strandfiat is more level and nearer the 

 sea surface, with a sharply defined edge at depths of about 10 to 20 metres. 



