I92I. No. II. THE STRAXDFLAT AND ISOSTASV. 243 



more submerged hv the slow rise of the general sea-level, the continental 

 plains keep to a certain degree their levels, owing^ to the upheaval of the 

 land compensating for the denudation. The denudation is, however, quite 

 insignificant in the lowest parts of the plains, the outer borders of which 

 will graduallv be submerg'ed by the rising sea. 



The difference between the level of the continental shelf and the 

 levels of the coastal continental plains as well as of the strandfiat. may 

 have been accentuated during the glacial periods when the general sea-level 

 was lowered more or less by the formation of ice-caps on land. 



Bv a negative shift of the sh.ore-line to an amount of say 40 to 60 

 metres, or more, tlie inner parts of the continental shelf may have been 

 more or less planed down by marine abrasion (shore erosion), and the 

 slope from the present coast, or from the edge of the submerged strand- 

 flat, mav have been cut back, and has become steeper. 



In the manner explained in this chapter it may be possible to under- 

 stand the development of the continental shc!f without being obliged to 

 assvune considerable changes in the general sea-level. There are, however, 

 certain bathymctrical features of the northern seas, which might seem 

 to indicate much greater changes in the sea-level. I may especially mention 

 the great similarity of the depths of 400 to 500 metres of the submerged 

 ridges between Scotland, The Færoes, Iceland, Greenland, and Baffin Land 

 Tcf. Xansen, 1904, pp. y^,, St, f., 89. 173 f.]. 



It seems somewhat difficult to assume that the uniformity of the 

 lowest levels of these ridges can merely be due to an accidental coincidence. 

 It may also be mentioned that the floor of the wide outer part of the 

 large submerged valley of the Barents Sea, south of Bear Island, which 

 [ have called the submerged Bear Island Channel [1904, p. 30], also seems 

 to have a level similar to that of the above mentioned ridges. The mouths 

 of several other suljmerged fjords (e. g. the A'est Fjord) also seem to have 

 similar depths. 



If these ridges and mouths of submarine fjords have actuallv been 

 lowered to some ancient base level, indicated by their present depth, this 

 would prfjbably mean a lowering of the general sea-level, so great that it 

 could hardly be explained by the shifts of sea-level discussed in this 

 chapter, and it seems extremely difficult to find a satisfactory explanation 

 of changes in the sea-level of this order. 



There is another possibilit\ that these depths mav indicate a certain 

 lower limit of the depth to which the Pleistocene ice-caps reached down 

 during their maximum development. A depth below water of 400 to 500 

 metres reached by an ice-sheet would correspond to a thickness of the ice 

 of about 440 to 550 metres, which does not seem excessive, even near the 

 edges of the ice-caps. Besides it has to be remembered, that during the 



