SLOPE - The degree of inclination to the horizontal. Usually expressed 

 as a ratio, such as 1:25 or 1 on 2^, indicating 1 unit rise in 2$, 

 units of horizontal distance; or in a decimal fraction (O.OU); 

 degrees (2° lO'); or percent ik%) , It is -sometimes described by 

 such adjectives as; steep, moderate, gentle, mild, or flat. 



SLOUGH - (pronounced - sloo): (l) A small muddy marshland or tidal 



vjatervjay which usually connects other tidal areas; (2) A tide-land 

 or bottom-land creek, 



SOIL CLASSIFICATION (Size) - An arbitary division of a continuous scale 



of sizes such that each scale unit or grade may serve as a convenient 

 class interval for conducting the analysis or for expressing the 

 results of an analysis. There are many classifications used; some 

 of those most often used are presented below: 



1. Wentworth' s Size Classification 



Grade Limits 

 (Diameters) 



Above 2^6 ram. 

 256 - 6k mm. 



6k - k rnm. 



k - 2 mm. 



2 - 1 mm. 



1 -r 1/2 imn. 

 1/2 - 1/k mm. 

 1/k - 1/8 mm. 

 1/8 - l/l6 mm. 

 1/16-1/256 mm. 

 Below 1/256 mra. 



Name 



Boulder 



Cobble 



Pebble 



Granule 



Very coarse aand 



Coarse sand 



i'ledium sand 



Fine sand 



Very fine sand 



Silt 



Clay 



2. U. S. Army Corps of Engineers' Classification 



Grade Limits 

 (Diameters) 



Name 



Above 305 mm. 

 76 mm - 305 mm. 

 19 mm - 76 mm. 

 U,7 mill - 19 ,mm. 

 1,9 ram - k*l mm 

 0.U2 - 1.9 mm, 

 0,07U - 0.14.2 minw 

 0,001 - 0.07ii mra, 



Boulders 

 Cobbles 

 Coarse gravel 

 Fine gravel 

 Coarse sand 

 Medium s,^d 

 Fine sand 

 Silt or clay 



A-31 



