In response to Charley Noble, I would say that the only sources I have are experience and skepticism. Leadbelly was a traditional singer and musician whose approach to music had nothing at all to do with academic categories. When traditional singers sing, they sing what they like. It is difficult for me to imagine that Leadbelly would *not* pick up songs from the Lomaxes and sing them the way he wished. Since "Haul Away Joe" - to my knowledge - has not otherwise been collected from Afro-American singers, there is at least as much chance that Leadbelly performed it with his own words and melody. I believe that any assumptions about a Mississippi River tradition behind the song must remain just that - assumptions, at least until further evidence appears.

The biography of Leadbelly published a number of years ago might clarify the matter, but I have not had access to it.