152 M. Charbaut on the 



the marl 5s carried away from beneath it ; the portions de- 

 prived of all support giving way to their enormous weight, 

 descend and break ; their debris are washed away by the 

 waters, rolled to a distance, and deep ravines or valleys are 

 left in their places. 



The better supported portions resist, but are mined at 

 their feet, their beds projecting over the edge of the ruptures, 

 are upset, are placed in inclined positions, and are curved 

 and contorted according to the form of the rocks on which 

 they rest. From thence the mountains and the various 

 forms taken by their beds. 



The caverns occurring on the oolitic mass, are owing to 

 some of these galleries, the roof of which being better sup- 

 ported, has only fallen in part. They are true subterranean 

 valleys. 



I have not the vain pretension of creating an universal 

 system. I merely state that I apply my reasoning solely to 

 the rocks in which I have observed the facts on which it is 

 founded. 



The valleys of Macornais, Lons le Saunier, Voiteur, &c. 

 form, at their commencement, the furrows in the platform 

 I have mentioned : they are afterwards prolonged across the 

 slopes and hills. 



The general aspect of their elevated sides is that of a wall 

 of rocks, which is surmounted by a rocky and almost vertical 

 formation, covered by heaths, and from which descends 

 with an uniform slope a fertile bank, covered with excellent 

 vines. 



The line of junction of the rocky wall with the kind of 

 prop commencing at its foot, is precisely at the separation of 

 the two enormous masses of limestone and marlj we are 

 always certain of finding the ferruginous oolitic bed there; 

 this line follows the slight inflexions of the beds, that are 

 generally almost horizontal. 



The action of the air and water decomposing the marls 

 that support the limestone beds, would mine the foot of the 

 escarpment until the fallen masses covering the marls with 

 debris should protect them from the atmosphere ; since then 



