98 THE BEAUTIES OF NATURE CHAP. 



ish Columbia, and turned them into a suc- 

 cession of pools or marshes, but this is a 

 slight matter compared with the action of 

 earthworms and insects 1 in the creation of 

 vegetable soil ; of the accumulation of ani- 

 malcules in filling up harbours and lakes ; 

 or of Zoophytes in the construction of coral 

 islands. 



Microscopic animals make up in number 

 what they lack in size. Paris is built of 

 Infusoria. The Peninsula of Florida, 78,000 

 square miles in extent, is entirely composed of 

 coral debris and fragments of shells. Chalk 

 consists mainly of Foraminifera and fragments 

 of shells deposited in a deep sea. The num- 

 ber of shells required to make up a cubic inch 

 is almost incredible. Ehrenberg has estimated 

 that of the Bilin polishing slate which caps 

 the mountain, and has a thickness of forty 

 feet, a cubic inch contains many hundred 

 million shells of Infusoria. 



In another respect these microscopic organ- 



1 Prof. Drummond ( Tropical Africa) dwells with great force 

 on the manner in which the soil of Central Africa is worked up 

 by the White Ants. 



