DOMAIN V. CALCAREOUS. 



Lined with a considerable quantity of argil. The 

 others have seldom attracted especial observation ; 

 and the division indeed cannot be regarded as of 

 much importance, as even in geology the granular 

 marbles cannot always be regarded as primitive, 

 nor the earthy as secondary. 



Most of the compact marbles also contain shells, 

 so that they belong to the next subdivision. 



STRUCTURE III. CONCHITIC. 



Of Bieyberg. The most beautiful and celebrated of this kind 

 is a recent discovery, being found at Bieyberg in 

 Carinthia, where it appeared in a bed of common 

 limestone, above a vein of lead. It is unfortu- 

 nately brittle, so that pieces of a large size cannot 

 be obtained. It is a grey marble, or fine lime- 

 stone, reflecting the red, green, and blue tints of 

 the opal, and almost with equal fire. These ex- 

 quisite colours arise from the laminar naker, or 

 what is commonly called mother-of-pearl, of a 

 kind of nautilus, of which fragments are imbedded 

 in this splendid substance ; their lustre being pro- 

 bably heightened by the fine reflections of iron, 

 observable in that of Elba, for veins of elegant 

 pyrites are not unusual in this stone. 



The name of Lumachella, which in Italian sim- 

 ply implies snail or shell marble, now begins to 





