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the grandeur of these subterranean caverns, and contribute, 
in no small degree, to alter the character of the whole mass. 
A considerable quantity, however, finds its way into our 
rivers and ultimately into the sea, without being deposited ; 
and hence our present seas should be gradually becoming 
saturated like the primeval ones. A similar little polypus 
is also busily engaged in these localities where the earthy 
matter is just on the point of being deposited, and there 
it is building up a beautiful fabric which is shortly to become 
an island, and ultimately to be subjected to a similar process 
of solution as those from which it is derived. Myriads of 
little mollusca also seize upon the limestone by destroying the 
carbonic acid which held it in solution, and transform it into 
a mass of shell, and these, after the death of the animal 
which produced them, is deposited with the general mass. 
Changes of precisely the same character, though on a much 
less extensive scale, are in operation at the present time, as 
appear to have operated in the formation of limestone at an 
earlier period ; altogether presenting to us a part of a won- 
derfully devised plan which cannot but excite our admiration. 
We observe the formation of this limestone tending to 
purify the atmosphere and rendering it suitable to the 
existence of man ; changes taking place within its mass 
which furnish him with metals and other objects of his 
wants; and extensive decompositions on its surface which 
supply him with the very means of existence. And although 
we picture to ourselves a time when these hills will be 
reduced to level plains by the powerful agency of carbonic 
acid and water, yet we are bound to believe that these im- 
measurable masses are contributing to the formation of 
submarine deposits, which ultimately may become dry land, 
and, in their turn, become covered with luxuriant vegetation 
adapted to all his uses. 
