WHAT IS THE STORY OF THE FOSSILS? 



water. Land animals and the stems and leaves of plants 

 could only be deposited close to the shore. Corals could 

 only be buried in deposits in warm water. Plants which 

 grow only in arctic regions indicate cold water. Thus 

 fossils can tell something of the climate of regions of the 

 earth millions of years ago. Fossils of salt-water life dis- 

 close the fact that there have been seas where now it is land. 

 The relative positions of different layers of rock often tell 

 the relative ages of the different kinds of life on the earth. 

 In some parts of Arizona and other places, you can visit 

 petrified forests. Great trees which have been changed 

 to solid rock lie here and there. Some are formed of 

 beautiful agate or other precious materials. These trees 

 were buried by volcanic material, and the mineral matter 

 dissolved in the water replaced the woody fiber and pre- 

 served the form of the tree. In many parts of the 

 country, various animal remains, such as corals, shell, and 



These animals were trapped in the famous tar pits of La Brea, near Los Angeles. 



An elephant and wolves have been caught in the soft tar and the saber-toothed 



tiger will soon suffer the same fate. 



