LAND AND WATER AREAS 69 



do not always maintain the same relation to each other. 

 Areas which at one time were land have since become sea 

 and those which were once sea are now land. Sea shells 

 are found imbedded in the rocks far from the' sea and 

 old river valleys are found by soundings under the sea 

 at considerable distances from the present mouths of the 

 rivers. What were once sea beaches are now found hun- 

 dreds of feet above the sea. 



From some such marks on the coast of northern Sweden 

 it appears that the coast has risen about seven feet during 

 the last 150 years. The Netherlands are sinking. Ob- 

 servations along the coast of Massachusetts give reason to 

 believe that it is sinking very slowly. Indications of the 

 movement of the land in respect to the sea are found in 

 all parts of the world. 



OLD SEA BEACHES, SAN PEDRO. 

 Three old beaches can be distinctly seen on the promontory . 



Old sea beaches are found rising one above the other 

 along the entire slope of a high hill at San Pedro, near the 



