140 



the carbonats or sulphat of lime. The solubi- 

 lity of these substances appears to have favored 

 the action of the subterraneous waters for ages. 

 The primitive limestone presents spacious ca- 

 verns, as well as transition limestone*, and that 

 which is exclusively called secondary. If these 

 caverns be less frequent in the first, it is be- 

 cause this stone forms in general only layers 

 subordinate to the mica-slatef, and not a sys- 

 tem of particular mountains, into which the 

 waters may filter, and circulate to great dis- 

 tances. The erosions occasioned by this ele- 

 ment depend not only on it's quantity, but also 

 on the greater or less time it remains, the velo- 

 city it acquires by it's fall, and the degree of 

 solubility of the rock. I have observed in ge- 

 neral, that the waters act more easily on the 

 carbonats and the sulphats of lime of secondary 

 mountains, than on the transition limestones, 

 which have a considerable mixture of silex and 

 carbon. On examining the internal structure 

 of the stalactites, which line the walls of ca- 



* In the primitive limestone are found the Kuetzel-Ioch, 

 near Kaufungen, in Silesia, and probably several caverns in 

 the islands of the Archipelago. In the transition limestone 

 we remark the caverns of Elbingerode, of Rubeland, and of 

 Scharzfeld, in the Hartz ; those of the Salzflueh in the Gri- 

 sons ; and, according to Mr. Greenough, that of Torbay in 

 Devonshire. 



•j- Sometimes to gneiss, as at the Simplon, between Dovre- 

 do and Crevola. 



