3o6 FKIDTJOF NANSEN. M.-N. Kl. 



tlic iiKiuiitains, iii ^\l)icll ca>c tlicir licij^^lits al)o\c tlic- sea may jxjssildy be 

 rc'lucc'l t'\cn rlurinj^'' the fii>l staj^c of erosion. 



As the erosi\c effect of a ino\inj^'- ^Hacicr is so enormously incrca.sed 

 with the \elocit\' of the movement (jirohahly l)y the thirrl power f)f the 

 \'elocit\, ct. p. 21) the rleniiilat ion of the laiul canserl h\- tlie erosion of 

 a hi*,'' ice-cap \\ ill oh\ iousl\ he coiiceiitratefl on the deepeninj^' of tlie \alleys 

 anrl fjorrls, while the surface of the higher jjarts of the mountains between 

 them may l)e comparatively little rlemulerl. 



Hence the final isostatic uphea\al arisinj^- from tins flenu'lation may 

 ha\e a tenflenc\- to increase the height above the sea of the mountains 

 and the land between the much deepened valleys and fjords. As has 

 previousK been pointed out, the strandfiat may f;robably ha\e been some- 

 what ele\ated in this manner after its formation, althouj:jh the jjrobabilitv 

 is that the ])resent elevation of the strand flat .above sea-level is lar,tfely 

 <lue to a clians.;t' in the sea-level itself. 



