CLAY. See SOIL CLASSIFICATION. 



CLIFF. A high, steep face of rock; a precipice. See also SEA CLIFF. 



CNOIDAL WAVE. A type of wave in shallow water (i.e., where the depth of water 



is less than 1/8 to 1/10 the wavelength). The surface profile is 

 expressed in terms of the Jacobian elliptic function (m u; hence the term 

 cnoidal. 



COAST. A strip of land of indefinite width (may be several kilometers) that 



extends from the shoreline inland to the first major change in terrain 

 features. (See Figure A-1.) 



COASTAL AREA. 

 A-1.) 



The land and sea area bordering the shoreline. (See Figure 



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 180 meters) 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 elevation with 

 relation to a DATUM. It is called an ISOBATH when connecting points of 

 equal depth below a datum. Also called DEPTH CONTOUR. 



CONTROLLING DEPTH. The least depth in the navigable parts of a waterway, 

 governing the maximum draft of vessels that can enter. 



CONVERGENCE. (1) In refraction phenomena, the decreasing of the distance 

 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. 



A- 7 



