442 DOMAIN V. CALCAREOUS. 



^ * s ^ en ^ u ^ ^ marme shells, and lies super- 

 incumbent upon slate or sandstone : some have 

 even confounded compact limestone with sand- 

 stone. Patrin has observed that the calcareous 

 deposition was more abundant on the summit of 

 mountains than on their sides, because the slopes 

 scarcely received, on a hundred fathoms of sur- 

 face, the same quantity with ten fathoms of the 

 level summit*. Hence the latter is sometimes 

 insulated and separated from that of the plains, 

 because the thin beds on the sides of the moun- 

 tains were worn down by the waters; and as the 

 summits of the mountains attract clouds, so un- 

 der the primeval waters they must have attracted 

 the various substances contained in them. 



The calcareous chain of the Pyrenees is far 

 higher than the granitic, containing marine 

 shells, and sometimes assuming the combination 

 called orsten, or swine-stone, a sort of coarse 

 fetid marble. Such is the summit of Mont 

 Perdu, a calcareous colossus, about twenty miles 

 in length, and four or five miles in breadth, with 

 an elevation of 10,500 feet above the level of 

 the sea. 



Bridas. Sometimes the calcareous beds on the steep 

 slopes have rolled down, and the broken frag^ 



* Min. iii. 16. 



