260 THE EARTH'S CRUST 



considerable distance from its edge. Along the shore are 

 marshes and lagoons bordered on their seaward side by sand 

 reefs, where the winds have piled up the sand brought in by 

 waves. In some places these sand reefs are so situated that 

 they are valuable for habitation, as at Atlantic City, New 

 Jersey, where a large summer resort has grown up, or along 

 the coast farther south, where a sparse population finds 

 its home on the broader reef. 



A coastal plain increasing in width toward the south 

 extends from New York to the Gulf. The western coast 

 of Europe has a considerable plain of this kind. The 

 Netherlands are situated on land which has been either 

 reclaimed from the sea naturally in recent geological time 

 or artificially by man in recent historical time. In the 

 southern part this reclamation is largely due to the sedi- 

 ment brought down by the Rhine. 



In the western part of the United States the coastal 

 plain is not as well developed as on the Atlantic border. 

 But the region about Los Angeles is a coastal plain, and 

 almost all the characteristics of the broad eastern plain can 

 be seen in traveling from the ocean to the coast mountains. 



Coast Effects Due to Downward Movement of the Earth's 

 Crust. Experiment 83. Cover a small board with a piece of thin 

 oilcloth which has been most irregularly crumpled. Take the 

 board by one edge and inclining it slightly gradually submerge it 

 in a dish of water. What kind of a line does the water form where 

 it meets the oilcloth? In what way would this line change if the 

 oilcloth were more crumpled ? If it were less crumpled ? If the 

 board is more submerged, does the position of the water Ijne change ? 

 Why does its form materially alter? 



Along a coast which has been depressed, the shore line 

 has moved landward, and a surface rendered irregular by 



