106 General View of the Mode of Formation of Iceland. 



under the might of the volcano, like Pompeii and Hercula- 

 neum, they were buried beneath showers of ashes, and some- 

 times sunk under the sea by secular movements, but they 

 afterwards again rose up. At present, their remains are fre- 

 quently found covered by huge mountain masses, and appear 

 as surturbrand in the masses of tuffa, and enable geologists 

 to discover a series of revolutions, in which one supplants 

 the other, but all of which have, more or less, contributed 

 their share towards the formation of the island. 



From the northerly situation of Iceland, it could not hap- 

 pen otherwise than that the sea should begin to freeze on the 

 shores of the very gradually increasing island, especially in 

 the Fiords, which now lie dry, in the form of narrow val- 

 leys, and that next spring, during the breaking up and drift- 

 ing of the ice, there should be formed those striae and po- 

 lished surfaces, which have been raised, by succeeding ris- 

 ings, to the height of two or three thousand feet, and which 

 are erroneously taken for glacial striae. At the time of the 

 first formation of Iceland, the formation of a glacier was quite 

 impossible ; this first occurred in more recent times, after, 

 not merely individual points, but whole i-anges of mountains 

 had reached a height far above the snow-line. 



That the glaciers descend from the snow-line into lower 

 grounds is a known fact ; here nature herself fixes their 

 boundary, their advance and retreat take place within mo- 

 derate limits, and are determined, partly by the configuration 

 of the rocks, and partly by the climate. 



The more Iceland rose out of the sea, so much the more 

 were its plateaux and its mountains enlarged, and, along the 

 valleys, rivulets and rivers now flowed. They began to cut 

 through the traps and tuflPas, carrying along the disintegrated 

 rocks or debris, and depositing them in the shape of alluvium, 

 in the hollow^s, in the valleys, in the fiords, and on the sea- 

 shore. The volcanic sand is particularly well adapted for 

 this. Through it arise, in a special manner, at the foot of the 

 southern volcanoes, those horizontal, though more frequently 

 slightly upraised promontories, called the Sandr or Oerafen. 

 In those parts where alluvium accumulates in the valleys, 

 and the rivers have only a slight fall, there appear, as in the 



