PHYSICAL GEOGRAPHY 



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its surface. The Katla eruption, in this way, converted thickly in- 

 habited and fertile tracts into deserts, and in 1362 Oraefajokull de- 

 stroyed, in the same way, two parishes, sweeping away forty farm- 

 steads with their inhabitants and live-stock and all else, out into 

 the sea. 



The best-known Icelandic volcano is Hekla. It has been the 

 scene of 21 eruptions during historic times; next in importance 

 comes the glacier-volcano Katla of which 13 eruptions are recorded. 



Fig. 11. Kverkfjoll, a volcano on the northern edge of Vatnajokull ; seen from Hvannalindir. 



(Phot. J. P. Koch.) 



Submarine eruptions have taken place some ten lo twelve times near 

 Eldeyjar off Reykjanes, whereby new islands have had their origin; 

 but these have disappeared again. Several volcanoes .are present 

 beneath the ice-cap of Vatnajokull, but the foci of eruption are not 

 known for certain. During the last two centuries, from 30 to 40 

 eruptions have been recorded from the snow-fields of Vatnajokull. 

 During several of these eruptions the snow and ice on SkeiSarar- 

 jokull, on the southern side, partially melted, and enormous torrents 

 of water were discharged. Occasionally Bruarjokull, on the northern 

 side, has been very active. On Reykjanes there are numerous pre- 

 historic volcanoes and rows of craters, and in three or four places 

 eruptions have taken place since there have been settlements on 



