sufficient quantities to permit drawing boundaries between different 

 sediment types, U. S. nautical chart notations of bottom material have 

 been defined by W. H. Berninghausen* and his definitions are used as 

 the basis for geologic interpretation of these data in the Naval 

 Oceanographic Office. 



The number of sediment notations on nautical charts varies 

 geographically with water depth. Since hydrographic surveys are made 

 primarily to locate dangers to navigation and to chart areas of shoal 

 water having depths less than the draft of ships, most soundings and 

 consequently bottom sediment notations are in shoal near shore waters 

 of 25 fathoms or less. The number of nautical chart notations also 

 depends on the country which produces the chart. Japanese and 

 Portuguese charts are remarkable for printing a notation of the bottom 

 type for alnnost every sounding. On some Japanese and Portuguese 

 large scale nearshore charts, notations exceed 50,000 per one-degree 

 quadrangle. Such density of information permits highly exact and 

 detailed delineation of sediment types. 



The use of bottom notations on foreign nautical charts is complicated 

 by the language barrier. Nautical chart notations appear in 16 major 

 foreign languages (not including national variations such as between 

 Spanish and Argentinian) and pose the dual problem of translation to 

 English and of determining if the definition of the foreign term is 

 fully equivalent to the definition of the English term. An example of 

 this problem is "st." which is "stein" on German charts and "stone" 

 on British Admiralty charts. It is difficult to determine whether the 

 British use "stone" as synonymous with "rock" to denote a specific 

 range of grain size, or generally to include material ranging from fine 

 gravel through boulders to bedrock reefs, or possibly to indicate lack 

 of specific knowledge of the bottom except that it is hard. It is even 

 more difficult to deternaine if the German use of the term corresponds 

 to the British use, and to equate both to some term in the U. S. classi- 

 fication of bottom materials, which does not include "stone" as a 

 separate category. 



III. Bottom Sediment Chart Compilation 



Several types of bottom sediment charts can be prepared showing 

 the geographic distribution of various properties of submarine surface 

 sediments. However, only four major types of sediment charts can be 



*BERNINGHAUSEN, W. H. The Quality of the Bottom, a Glossary of 

 Terms, U. S. Navy Hydrographic Office, SP-56, 11 p., November 1961. 

 Washington, D. C. 



