COASTAL AREA - The land and sea area bordering the shoreline. (See 

 Figure A-1.) 



COASTAL PLAIN - The plain composed of horizontal or gently sloping 

 strata of clastic materials fronting the coast, and generally 

 representing a strip of sea bottom that has emerged from the 

 sea in recent geologic time. 



COASTLINE - (1) Technically, the line that forms the boundary between 

 the COAST and the SHORE. (2) Commonly, the line that forms the 

 boundary between the land and the water. 



COBBLE (COBBLESTONE) - See SOIL CLASSIFICATION. 



COMBER - (1) A deepwater wave whose crest is pushed forward by a strong 

 wind; much larger than a whitecap. (2) A long-period breaker. 



CONTINENTAL SHELF - The zone bordering a continent and extending from 

 the low water line to the depth (usually about 100 fathoms) where 

 there is a marked or rather steep descent toward a greater depth. 



CONTOUR - A line on a map or chart representing points of equal eleva- 

 tion with relation to a DATUM. It is called an ISOBATH when con- 

 necting points of equal depth below a datum. 



CONTROLLING DEPTH - The least depth in the navigable parts of a water- 

 way, governing the maximum draft of vessels that can enter. 



CONVERGENCE - (1) In refraction phenomena, the decreasing of the dis- 

 tance between orthogonals in the direction of wave travel. Denotes 

 an area of increasing wave height and energy concentration. (2) In 

 wind-setup phenomena, the increase in setup observed over that which 

 would occur in an equivalent rectangular basin of uniform depth, 

 caused by changes in planform or depth; also the decrease in basin 

 width or depth causing such increase in setup. 



CORAL - (1) (Biology) Marine coelenterates (Madreporaria) , solitary or 



colonial, which form a hard external covering of calcium compounds, 

 or other materials. The corals which form large reefs are limited 

 to warm, shallow waters, while those forming solitary, minute 

 growths may be found in colder waters to great depths. (2) (Geology) 

 The concretion of coral polyps, composed almost wholly of calcium 

 carbonate, forming reefs, and tree- like and globular masses. May 

 also include calcareous algae and other organisms producing cal- 

 careous secretions, such as bryozoans and hydrozoans. 



CORE - A vertical cylindrical sample of the bottom sediments from which 

 the nature and stratification of the bottom may be determined. 



COVE - A small, sheltered recess in a coast, often inside a larger 

 embayment . (See Figure A- 8.) 



A-7 



