"For example, I'm reminded of a Mudcat thread from a month or so ago, where someone discovered an old music-hall-type song with long and detailed lyrics about having one's grave kept "green," and proposed that this number was superior to, and must have preceded, the blues classic 'One Kind Favor (See That My Grave Is Kept Clean).'"

Hold on, Poppagator! I think I'm the individual you are refering to, and I definately did not say that "See That My Grave's Kept Green' was superior to Blind Lemon Jefferson's classic. In fact, I said quite the opposite. I did suggest that it was possible that Jefferson's song drew from the earlier parlor song. Here is what I wrote:

"I came across this while looking up something else. I think it's an excellent example of the degree to which recomposition of an original song can create a new (and in this case, better) song."

And you did respond, quite eloquently. I would have liked to have continued the discussion, but I couldn't find any relevant variants between the 1876 sheet music and Jefferson's recordings.

Back to this discussion: If Jefferson's song is related to the 1876 parlor song, it is a perfect illustration of folk genius at work. Out of commonplace or maudlin sources, something trancendent is created.