I KlinjOK N'ANSKN. M.-X. Kl. 



fjords, where the inilial i)rej^lacial ("palæic"; mountain surface rnav still 

 be recognizable. 



In the above manner we alsf) obtain a natural ex|)lanation why the 

 fjords are so very narrow, deej), and often winding-, in regions of hard 

 and resistant Archæan and igneous rocks, in western Norway and in 

 Greenland, while in regions with weak'cr rocks, tliey are wider, less deep, 

 and often radiating (Ait from the central region of the land, as they do 

 on Iceland, in Finmarken, and partly on Spitsbergen. 



In regions composed of resistant rocks, the big, inoving glaciers of 

 the glacial periods eroded chiefly vertically. The horizontal erosion, by 

 frost on their sides, has been comparatively small. They were guided by 

 the initial preglacial valleys, formed by the subaërial denudation greatly 

 along lines and zones of fracture and weakness. The glacial erosion 

 followed the same lines. As the outflow from the inland ice converged 

 into these narrow channels, the velocity of their ice streams became very 

 great, and the vertical erosive power of the latter enormously intensif ed. 



In regions of less resistant rocks, the initial preglacial valleys were 

 broader, the glaciers would be more able to take their own course, and 

 their erosion would not be so exclusively vertical, but also to some greater 

 extent horizontal, especially because the mountain slopes on their sides 

 were much more rapidly destroyed by frost. The glaciers would thus 

 widen out, be less deep, and would obtain much smaller velocities. 



A common effect of this erosion in such regions will therefore be 

 that the fjords become comparatively shallow and wide, and they often, 

 as on Iceland and in Finmarken, become wider towards their mouth, while 

 in regions of resistant rocks they are generally narrower towards their 

 mouth than further inland, wdiere they are excavated into much deeper 

 troughs, or true rock basins. 



It has already been pointed out on a previous page that the glacial 

 erosion has been of much importance for the development of the strandfiat 

 by dissecting the coast and splitting it up into innumerable peninsulas, 

 islands, and skerries. Thus the coast line, or the line of attack, has been 

 enormously increased, and the subaërial denudation, as well as the marine 

 denudation, have been greatly facilitated. 



Otherwise the erosion of the inland ice, and its outflowing glaciers, 

 can have been of no direct importance for the planing of the horizontal 

 level of the strandfiat, as far as I can see. 



When the big glaciers carved or deepened the fjords and sounds tra- 

 versing the present strandfiat, the islands and peninsulas between them 

 may also have been denuded to some small extent where they were covered 

 by the moving ice. But the general denudation thus accomplished, cannot 

 have been considerable, as the movement of these marginal ice-sheets be- 

 tween the glaciers of the deep channels must have been relatively slow. 

 As the velocities of this motion must have varied much locally, the depth 



