BENCH MARK (B.M.) - A fixed point used as a reference for elevations, 



BERI'Ij BEACH - A nearly horizontal portion of a beach formed by the de- 

 posit of material by wave action. Some beaches have no berms, 

 others have one or several. CSee Figure A-l) 



BERM CREST - The seaward limit of a berm. Also BERM EDGE. 

 (See Figure A-l) 



BIGHT - A slight indentation in the shore line of an open coast or of 

 a bay, usually crescent shaped. (See Figure A-8) 



BLIND ROLLERS - Long, high swells which have increased in height, al- 

 most to the breaking point, as they pass over shoals or run in 

 shoaling water. 



BLUFF - A high steep bank or cliff. 



BOLD COAST - A prominent land mass that rises steeply from the sea. 



BORE - A tidal flood with a high, abrupt front, (e.g. such as occurs 

 in the Amazon in South America, the Hugli in India, and in the 

 Bay of Fundy.) Also EAGER. 



BOTTOM - The ground or bed under any body of water; the bottom of the 

 sea, (See Figure A-l) 



BOTTOM (NATURE OF) - The composition or character of the bed of an 

 ocean or other body of water; (e.g. clay, coral, gravel, mud, 

 coze, pebbles, rock, shells, shingle, hard, or soft.) 



BOU"LDER - A rounded rock more than 12 inches in diameter; larger than 

 a cobble stone. 



BREAKER - A wave breaking on the shore, over a reef, etc. Breakers 

 may be (roughly) classified into three kinds although there is 

 much overlapping: 



Spilling breakers break gradually over q\iite a distance; 



Plunging breakers tend to curl over and break with a crash; 



and 



Surging breakers peak up, but then instead of spilling or 



plunging they surge up the beach face. (See Figure k-h) 



BREAKER DEPTH - The still water depth at the point where the wave 

 breaks. Also BREAKING DEPTH. (See Figure A-2) 



BREAPaTATER - A structure protecting a harbor, anchorage, or basin 

 from waves. 



A-l; 



