584 



STRUCTURE AND LIFE HISTORIES 



the following table, the older rocks being at the bottom, 

 the most recently formed at the top. 



509. Paleogeography. — By changes in the relative 

 level of the land and sea, above referred to, rocks contain- 

 ing fossils may be elevated as dry land, and frequently 

 as mountains, so that remains of marine organisms, as 

 well as of others, are often found at high elevations. In 

 some.cases forests near the seashore have been submerged, 



