278 Natural History of Volcanos and Earthquakes. 



We shall endeavor to show in our next section what eflfect 

 might be expected on the surface of the earth, if its sohd crust 

 should still continue to increase in thickness towards the interior 

 by gradual consolidation of the fluid centre. Besides, I think 

 that a sinking of the outer crust can scarcely be supposed to 

 occur, but that it is much more probable that caverns should be 

 formed at the moment when the fluid mass becomes solid. At 

 least the latter effect was seen in fusing two basalt balls, two feet 

 in diameter, in which many larger and smaller cavities were 

 found. I shall allude to these phenomena in another section. 



If we take into consideration all that has been already said on 

 ejections and elevations, [soulevemens,) we shall be induced to 

 adopt the following inferences. Masses of our earth, still in a 

 fluid state, may be raised through and above its solid crust. The 

 rising of the lava in the craters of volcanos is a satisfactory proof 

 of this circumstance. Solid rocky masses, strongly heated, may 

 be pushed upwards during violent convulsions, and elevations of 

 the original rocky covering, or be thrown up in the form of loose 

 masses, more or less heated. The not unfrequent rising of small 

 islands from the bottom of the sea, and the elevations [souleve- 

 mens) actually observed to take place in the continents, are evi- 

 dences of these operations. All these phenomena are effects of 

 forces, which develope their whole intensity in a very short time, 

 often in a few moments. But large islands, and even whole coun- 

 tries may, in a very short time, be raised several feet, as was 

 shown in the cases of Chili and Santa Maria. On the other 

 hand, Scandiiiavia presents us with an instance of an elevation 

 which, compared with the preceding, takes place with extraordi- 

 nary slowness. 



Besides all these elevations which have been actually observed, 

 other appearances occur, which lead us to infer that elevations 

 have taken place previous to the existence of any record. These 

 are the elevations of old volcanic masses, as basalt, trachyte, &c., 

 their penetration into fissures, and the elevation of whole systems 

 of mountains. In regard to the first, the conclusion may, as has 

 been already shown, be considered as well founded as it is gen- 

 erally possible to be, when drawn from phenomena which have 

 taken place before any records were in existence. The similarity 

 between these phenomena, and those which have taken, and still 

 take place, before our eyes, render it extremely probable that they 



