124 THE JOURNAL OF GEOLOGY. 



An estimate of the volume of rock matter which is carried by 

 the glacial rivers of Greenland and Norway proves also that the 

 glacier denudation in a few thousand years must reach great 

 dimensions. 



When thus the capacity of the rock basins comes short of hold- 

 ing the known glacial sediment (the quantitative element), the 

 form of the basins (the qualitative element) is quite in harmony 

 with those we find in other glaciated countries and nozvhere else. 

 Both the lakes and the fjords have a distinguishing trough shape, 

 with flat bottoms and comparatively steep sides, in the transverse 

 section, and, in the longitudinal section, a gradual deepening 

 toward a point that is situated not very far from the outer end, 

 against which it more suddenly shoals up. This form cannot be 

 generated by any other possible eroding agent than glacier ice. 

 The fissure theory is out of the question, as exact sections specific- 

 ally show. Faults and dislocations cannot account for their 

 specific form and their relations to quite superficial topographical 

 features. The admirable monograph on the Kristiania fjord, by 

 Professor W. C. Brogger, makes it also quite clear that its dis- 

 tinguishing fjord character can only be of glacial origin. Basins 

 of this form, as is well known, are restricted to glaciated coun- 

 tries ; and they can be deduced directly from the motion of the 

 eroding glacier. The movement must accelerate towards the 

 point where the ice surface intersects the snow line, where the 

 surplus ice from the whole glacier must pass. Thence it must 

 slacken because of the melting farther down. The erosion, which 

 naturally must depend both on the movement and the pressure 

 of the ice, will decrease accordingly. In this we find the explan- 

 ation both of the longitudinal form of the glacial basins, and 'of 

 their evident dependence on the margin of the land ice. 



So much may be said about glacial erosion by way of intro- 

 duction before entering into the study of the succession of glacial 

 events in Norway. We must be somewhat prepared to face the 

 greatness of the phenomena, which only glacial studies can make 

 more familiar to us. 



When we try to realize the appearance of Norway \xv pre- 



