MOUNTAIN FORMATION 



height of Mount Pelee, and therefore at a height of 

 5143 feet above the sea-level. A violent eruption would 

 reduce its mass and its steeple-like pinnacle ; but after its 

 losses it generally pushed up again. Professor Heilprin 

 at last got near enough to observe it, and the obelisk was 

 found to be not of pumice stone, as had at first been 

 suspected, but of the hard rock we have mentioned. It 

 had, in fact, been comparable to a Titanic cork of rock 

 which had closed up some vent far down in the crust of 

 the earth, and which had at last been lifted by the steam 

 pressure beneath it. It finally sank back into the crater, 

 but it was replaced by a dome of rock which underwent 

 similar changes in height, though on a smaller scale, to 

 those of the obelisk. The dome of rock was, however, 

 on a more massive scale even than the obelisk, and at one 

 period of its career a spine, 100 feet in height, like a 

 smaller obelisk, was pushed up through its middle. This 

 dome was examined by the explorers, the Abbe Yvon and 

 M. Beaufroy, who found that the dome was a great mass 

 of andesite, while about it were fragments of the rock of 

 which the obelisk had been composed. They wrote at 

 the time : 



"It is an error to suppose that there exists in the 

 bottom of Mount Pelee a hole from which lava and gases 

 have come out. At present there is a tremendous cork of 

 andesite, which is called the 'Dome,' and which must 

 have as its dimensions a diameter half a mile across at its 

 base and a height of about 1200 feet. On all sides of 

 the dome there are fumaroles (small cone-like craters), 

 some of which throw out a reddish smoke, others of which 



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