CH. XL. PRINCIPLES OF GEOLOGY. 445 



Then to account for the huge masses of basalt and lava 

 which are found in the earth's crust, he reminded his 

 readers of the great eruption of the volcano called Skaptar 

 Jokul in Iceland, which took place in 1783. In this erup- 

 tion the torrent of lava was ninety miles in length, from 

 seven to fifteen miles in breadth, and in some places 600 

 feet deep, and the whole mass poured out would have made 

 a mountain as big as Mont Blanc. 



He then went on to give accounts of the remarkable 

 earthquakes which have taken place in times of history : 

 the earthquakes in India, in Java, and especially in Cala- 

 bria, in 1783, when new lakes were formed by the sinking 

 in of the ground, and the rivers were made to run in new 

 channels. He showed also how the height of land is some- 

 times changed in volcanic countries ; as on the coast of 

 Italy, near Naples, where the ground on which the famous 

 Temple of Serapis stands can be proved to have been 

 raised and depressed twice even in historical times. 



And besides all these obvious changes which men cannot 

 help noticing, he proved that other quiet and unnoticed 

 risings and fallings of land are taking place ; as, for 

 example, in Norway and Sweden, where the land is rising 

 out of the sea in some places at the rate of about two or 

 three feet in a century ; and in Greenland, where it is sink- 

 ing, so that huts built near the shore have to be moved 

 inland, because they are becoming submerged in the sea. 



These are a very few of the facts which you can under- 

 stand, by which Lyell demonstrated that the surface of our 

 earth is always undergoing changes in our own day, and that 

 by similar changes going on in past times the whole of the 

 crust of our earth may have been built up and carved out. 

 In addition to this he showed how plants and animals are 

 now being buried in mud and earth, and how their remains 



