92 volcanoes; earthquakes. 



whole group of the Canary Islands rests upon 

 one volcanic hearth, over which each of these 

 islands was heaved up from the bottom of the 

 sea. 



The power which can bring about such vast 

 movements, must be a long time brooding and 

 gathering itself within, before it can vanquish the 

 resistance of the masses that are pressing it down. 

 At last it tears open the strata which form the bed 

 of the sea, and those that lie deeper down below 

 it, and uplifting them to the surface, escapes 

 through the openings thus made — the so-called 

 Craters of Elevation, or Upheaval. However, a 

 great part of the huge uplifted mass falls back 

 again, and soon shuts the opening, which would 

 not have been formed but for the enormous force 

 that rent it. No volcano is produced; but the 

 basalt rocks that were forced up generally remain 

 around the outer border of the crater, as witnesses 

 of the outburst that once had happened. The 

 Peake of Teyde rises up in the midst of such a 

 crater of upheaval of vast circumference, as a lofty 

 dome of trachyte. Through the opening in its 

 summit there is formed, between the atmosphere 

 and the depths within, a channel which can be 

 sealed at top, but not below, by the cooling and 

 falling in of the melted masses. Similar outward fea- 

 tures are found on all other central points of volcanic 

 activity. Their craters are the especial outlets of 



