S
sand
N/A
M
silt
mud
Sg
gravelly sediment
very fine sand
Gr
gravel
hardbottom
granules
Sr
very coarse sand
coarse sand
Gs
yes
fine sand
medium sand
silty sand
G
Sm
clayey silt
fine silt
very fine silt
Ms
medium silt
sandy silt
coarse silt
Rg
solid
fine pebbles
Rs
coarse pebbles
Mg