THE LIFELESS EARTH 



33 



by bacteria, the humus of the soil containing organic acids, 

 the soil derived from rocks which are broken up by bacteria, 

 and even the ooze from the ocean floor, both calcareous and 



TABLE I 



Average Distribution of the Chemical Elements in Earth, Air, and 

 Water at the Present Time ^ 



{Life Elements in Italics) 



silicious, formed from the shells of foraminifera and the skele- 

 tons of diatoms. Thus, before the appearance of bacteria, of 

 algas, of foraminifera, and of the lower plants and lowly inver- 

 tebrates, the surface of the earth was totally different from 



' Clarke, F. W., 1916, p. 34. 



