as psammitic pellite (sandy clay), arenaceous lutaceous argillite (sandy 

 silty clay), or psephitic argillaceous calcarenite (gravelly clayey 

 calcareous sand), each denoting fairly specific proportions of each 

 particle size class, 



4. Confusion also arises in combining particle size classifica- 

 tions with ones which denote chemical or mineral composition or 

 origin of the sediment. It is extremely difficult to determine exactly 

 what is meant by "coral sand, "i.e., whether it is coral (size of particle 

 may range from clay size to massive reefs) and sand, or sand sized 

 calcium carbonate grains of coral origin. Shell may describe moUusks 

 as large as giant clams or microscopic skeletal remains of pelagic 

 foraminifera. Rock and stone are very indefinite terms used to describe 

 a wide range of particle sizes, as well as solid bedrock outcrops or 

 reefs. Detritus, alluvium, and diluvium are terms which indicate 

 origin or mode of deposition, but they are used by many authors to 

 imply various particle size ranges. Volcanic ash and pumice indicate 

 origin and composition with unspecific grain size implications. The 

 terms mud and ooze are used in many different ways to indicate or 

 only to imply fine grain size, or to indicate plasticity, origin, or 

 composition. 



5. Determination of exact English equivalents of foreignlanguage 

 terms is difficult and often impossible. The term "wadden" often is 

 used in European journals to describe tidal flat sediments, but some 

 authors restrict it to mud or silts and clays, others include sand 

 sized grains, and many use it without defining it, Russian scientists 

 are not consiste^it in their use of terms such as mud, as the same 

 author (M. V. Klenova) equates it with silt on one page, equates it with 

 silt and clay on another, and uses it on a third page in a very general 

 sense of a "muddy" sediment which may include large proportions of 

 sand, gravel, pebbles, and shell. Thus, the lack of consistency in 

 analysis, definition, and reporting of bottom sediment data makes it 

 very difficult to adapt machine methods economically to their storage, 

 retrieval, and analysis. 



C. Nautical Charts 



Abbreviated designations of bottom type appear on nearly all 

 U. S. and foreign nautical charts. The notations of bottom material are 

 made from field descriptions of samples obtained in the course of 

 hydrographic surveys. Few of them are based upon laboratory analysis 

 of samples. They are subject to all of the inconsistencies listed above. 

 However, they are the only type of sedinnent information existent in 



