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THORODDSEN 



only 20 25, but upon the other side 30 35. There are, how- 

 ever, a few basalt mountains which are much steeper than this: 

 for instance Skessuhorn near Borgarfjor5ur, which has an inclination 

 of 48. In the numerous erosion-channels on the mountain sides, 

 where gravel and stones are constantly rattling down and avalanches 

 are frequent, it is difficult for the plants to gain foothold. The 

 ridses between the mountain streams are therefore more closelv 



/ 



covered with plants but, as already mentioned, a continuous plant- 



Fig. 13. Basalt mountains with snow-wreaths (IsafjorSur). 



covering rarely extends higher than half-way up on the basalt 

 mountains. In olden times the mountain sides were in very manv 



*/ */ 



places clad with coppice woods, but these disappeared at an early 

 date, partly owing to the havoc wrought by sheep and partly to 

 man's lack of foresight. Now only some stunted shrubby birches 

 are to be seen upon inaccessible cliffs, where they are beyond reach 

 of man and beast, even with the utmost exertion. Upon mountain- 

 sides deprived of their birch-copses, avalanches of snow and stones 

 have suffered no hindrance, so that all soil and plant-growth have 

 disappeared, thus turning the mountain-sides into naked, gravelly 

 and rocky slopes. In some districts such changes have taken place 



