THE ANIMAL KINGDOM. 35 



CHAPTEE IV. 



CITIES BUILT OF MICROSCOPIC SHELLS. 



When in following our studies progressively we pass 

 from organisms so small as absolutely to escape the eye, 

 to those the shell of which approaches a pin's head in 

 size, we see that these latter have really influenced geo- 

 logical phenomena, which have something prodigious in 

 them. 



This is the case with the Miliolae, little shells which 

 owe their name to the fact that their size does not exceed 

 that of a grain of millet, and indeed is often less. They 

 were so numerou.s in the Parisian seas, that in settling 

 down they formed mountains, which are now quarried 

 to build our towns: the greatest part of the stone in 

 the houses of Paris is only composed of the carapaces 

 of molluscs, heaped up and closely cemented together; 

 so that one may say without hyperbole that our splendid 

 capital is built of microscopic shells. 



An observation by M. Defrance will give an idea of 

 the minuteness of the Stone Miliola, the species which 

 principally constitutes the coarse limestone used in 

 building. He has computed that a box with a capacity 

 of a cubic line would contain as many as ninety-six ! 



What a mystery envelops the life of these fragile 

 shells, which, in spite of their insignificant size, have 

 played such a great part in the telluric phenomena of the 

 tertiary epoch! Nature here reveals her infinite power 



