280 DESCRIPTION OF THE MUSEUM. 



Lastly, the pulverulent, more generally known 

 under the name i fossil-flour. 



Above the stage is the lithographic stone, dis- 

 covered a few years ago at Chateauroux, in the 

 department of Indre ; and which has all the qua- 

 lities of that of Bavaria, which was first employed 

 for that purpose. A specimen of the latter, from 

 Ingolstadt, is at the bottom of the case. 



The series of carbonate of lime (fourth and fifth 

 cases) is terminated by specimens of those varie- 

 ties of it, which have been denominated concre- 

 tions; they result from the filtration of a liquid, 

 charged with calcareous particles, through the 

 roofs of subterranean cavities. In proportion as 

 the drops, which remain suspended to these 

 arches, dry, the stony particles unite in a tube, 

 which elongates from successive deposits like 

 icicles : this kind of concretion is called stalactite. 

 A portion of the liquid falling from the roof to 

 the ground forms other deposits, generally mam- 

 millated, named stalagmites. These deposits some- 

 times increase so as to unite, and consequently 

 form enormous columns. We see such in the 

 grotto of Auxelle, in the department of Doubs ; 

 whence the beautiful stalactite, which is placed 

 between the windows in this room, was taken. 

 But of all the grottos of this kind, the most cele- 

 brated is that of Antiparos, in the Archipelago. 



