3o U.e So Bureau of Soil^ Classification 



Grade Limits 



(Diameters) Name 



2-1 mra. Fine gravel 



1 - 1/2 mrao Coarse sand 



1/2 - l/k mm. Medium sand 



l/k - 1/10 mm. Fine sand 



1/10 - 1/20 mm. Very fine sand 



1/20 - 1/200 mm. Silt 



Below 1/200 mm. Clay 



ko Atterberg's Size Classification 



Grac\e Limits 



(Diameters) Name 



2,000 - 200 mmc Blocks 



200 - 20 ram. Cobbles 



20 - 2 mm. Pebbles 



2 - 0.2 mmo Coarse sand 



0.2-0.02 om. Fine sand 



0.02 - 0,002 mm. Silt 



Below O0OO2 mm. Clay 



SOLITARY WAVE - A wave consisting of a single elevation (above the 

 water surface) of height not necessarily small compared to the 

 depth, and neither followed nor preceded by another elevation or 

 depression of the water surfaces. 



SORTING COEFFICIENT - A coefficient used in describing the distribution 

 of grain sizes i n a sam ple of unconsolidated material. It is de- 

 fined as Sq s °yQ]_/Q3, where Q]_ is that diameter which has 7$% of the 

 cumulative size-frequency (by wt«) distribution smaller than itself andl 

 2^% larger than itself, and Q3 is that diameter having 2^% smaller and 

 7^% larger than itself. | 



SOUND (noun) - (l) A wide waterway betxreen the mainland and -an island, 

 or a wide waterway connecting two sea areas. See also STRAIT. 

 (2) A relatively long arm of the sea or ocean forming a channel 

 between an island and a mainland or connecting two larger bodies^, 

 as a sea and the ocean, or two parts of the same bodyj usually 

 wider and more extensive than a STRAIT. 



SOUND (verb) - To measure or ascertain the depth of water as with sound- 

 ing lines, 



SOUNDING - A measured depth of water. On hydrographic charts the sound- 

 ings are adjusted to a specific plane of reference (SOUNDING 

 DATUM) . 



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