Also found a Google reference to slue / slough, and the following (US) definitions for slough:[
n]  any outer covering that can be shed or cast off (such as the cast-off skin of a snake) 
[n]  a stagnant swamp (especially as part of a bayou) 
[n]  a hollow filled with mud  
[n]  necrotic tissue; a mortified or gangrenous part or mass 
[v]  cast off hair, skin, horn, or feathers; of animals 
Not sure if that gets you anywhere!
Paul