IXTRODUCTOIIY : FOIOrATIOX OF FIORDS. 21 



toiu of these fiords above the surface of the water, while certain points higher 

 than the adjacent surface, but now deep beneath the water, woukl appear as 

 islands. Hence almost all fiord coasts are accompanied by outlying fx-ag- 

 ments of land of greater or less size, as is well illustrated on the Norwegian 

 coast; and also, in a higher degree, by the shores of British Columbia, from 

 Vancouver Island north. 



In considering the nature and origin of fiords, we are led irresistibly to the 

 conclusion long- since enunciated by Professor Dana, namely, that fiords are 

 evidences of subsidence ; the regions where they occur are those whei-e a 

 high mountain range has become partially submerged, so that the bottoms 

 of the deep valleys of erosion are now occupied by the sea. 



It has been claimed by some writers on this subject that the occurrence of 

 fiords in high latitudes is proof that the excavation and erosion which they 

 indicate to have taken place has been the work of ice. All that we have 

 observed, however, with regard to the amount of erosion which ice is capable 

 of effecting, leads us to infer that glaciers have had little to do with the mat- 

 ter ; unless it be that, to a certain extent, the filling by ice of vallej's already 

 formed has prevented their being afterwards occupied by the detrital ma- 

 terials which would necessarily accumulate in a mountain valley where the 

 slope was insufficient to give to running water the power to remove such 

 detritus, or where, from climatological changes, the amount of precipitation 

 has diminished, and thus the erosive action decreased, so that the gorges 

 could no longer be swept clean of the detritus carried down into them from 

 their borders of more or less precipitous rocks. 



The fact that the fiords are chiefly on the western side of the continents 

 has been insisted on as connecting their origin with the occurrence of areas 

 of great precipitation, the sides of mountain ranges in the extra-tropical lati- 

 tudes which are exposed to the return trade-winds being likely to receive a 

 much greater rain and snow fell than the opposite or eastern flanks of the 

 same chains. The abundant precipitation in the form of rain giving rise to 

 the deep gorges on the mountain sides which are afterwards to be converted 

 into fiords by the sinking of the region, the continuance of the same increased 

 precipitation in the form of snow, under those changed climatic conditions 

 which will be explained further on, causes these precipitous valleys to be- 

 come filled with ice, which carries the detrital material away on its surface, 

 and deposits it sometimes at a great distance from its source, as the icebergs 

 formed from glaciers coming down to the sea on the west coast of Greenland 



