IV-18 



is similar to that above the water, except where earth and rock have 

 eroded from the land above the water and been deposited on the land 

 under the water. The estuarine zone along formerly glaciated coasts 

 is a region of deep, heavily indented embayments, many islands, steeD 

 rocky shores, predominantly evergreen forests reaching nearly to the 

 water, irregular bottom topography, and vistas of great scenic beauty 

 (Figure IV. 1.9). 



The unglaciated parts of the Atlantic coast and of the Gulf coast con- 

 sist of relatively flat terrain in which coastal embayments and marshes 

 are the predominant estuarine features. These are coasts formed pri- 

 marily of sediments eroded from ancient mountains, and along which the 

 embayments and marshes form traps for sediments the rivers bring down 

 to the sea. 



The estuarine zones along these coasts may be of many forms, but the 

 general imDression is one of great expanses of shallow water and 

 aquatic vegetation, extensive sand dunes and sandy ocean beachfront, 

 and narrow and carefully maintained naviqation channels with port 

 facilities well inland (Figure IV. 1.10). 



The Pacific coast of the conterminous United States is actively being 

 eroded by wave action against the exDosed shoreline. The major 

 coastal feature is narrow beach or rocks at the base of steep bluffs. 

 Deep embayments behind headlands or shallow indentations in the coast 



