Wentworth published a classification for sediments that was a modification of the Udden scale from 1898.
|
Term
|
Diameter in mm
|
|
boulder
|
> 256
|
|
cobble
|
64 to 256
|
|
pebble
|
4 to 63.9
|
|
gravel
|
2 to 3.9
|
|
very coarse sand
|
1.00 to 1.99
|
|
coarse sand
|
0.50 to 0.99
|
|
medium sand
|
0.25 to 0.49
|
|
fine sand
|
0.125 to 0.25
|
|
very fine sand
|
0.0625to 0.124
|
|
silt
|
0.0039 to 0.0624
|
|
clay
|
0.0024 to 0.0038
|
|
colloid
|
< 0.0024
|
