436 DOMAIN V. CALCAREOUS. 



beds of which are so thick that the quarry seems 

 cut into one mass. It is reserved for bridges 

 and highways*. 



" This rock seems exclusively to belong to 

 the depositions of coarse sediment, which are 

 far from the primitive mountains, and which 

 approach the alluvial territory. Although it 

 present beds of great thickness and extent, it 

 never forms mountains, but only round hills, of 

 which the skirts sometimes display pretty high 

 precipices. It forms the base of many plains, 

 such as in France the plains to the south of 

 Paris, those in the neighbourhood of Caen, and 

 others. 



" The beds of this rock are very distinct, 

 being horizontal, rarely inclined, never convo- 

 luted nor bent, and commonly divided by clay, 

 marl, or sand. There are sometimes seen, be- 

 tween them, infiltrated geods of quartz and cal- 

 careous spar, as at Neuilly, near Paris ; or thin 

 layers of keralite or flint, interspersed with 

 shells, as at St. Cloud and Sevres. 



" These beds vary much in thickness ; and it 

 may be observed, that they are thicker in the 

 soft kinds than in the hard. The latter is often 

 in such thin layers that it is used in some coun- 



* One stone in the parapet of the celebrated bridge of Neuilly is 

 thirty-four feet in length. P. 





