INTERCHANGE OF SEA AND LAND 



251 



their roots penetrating the ocean floor just -as they stood 

 on dry land. It can be proved that an old temple near 

 Naples, Italy, has stood above and then in the sea more 

 than once since it was built. 



Sometimes old sea beaches are found high above the 

 shore and even at a considerable distance inland. Old 



OLD ROCK BEACH, IMPERIAL VALLEY, CALIFORNIA 



This is many miles inland, but it was once a part of the coast of 

 California. 



river valleys are located by soundings under the sea, well 

 out from the present mouths of rivers. From some markings 

 on the coast of northern Sweden, it appears that the coast 

 has risen about seven feet during the last 150 years. Obser- 

 vations along the coast of Massachusetts give reason to 

 believe that this coast is sinking very slowly. 



Facts like these show that the seacoast is not stable but 

 is subject to upward and downward movements, some of 

 which are slight, and others great. 



