This could be a source, or close to it, of the song sung by Macon and others.

From Merry Songs by Samuel Conrad Hanson (Chicago: A. Flanagan Company, 1889) where it is printed with its melody. The chorus is in 4-part harmony:

I'S A GWINE BACK SOUF.

[Editor's note:] This is a representation of a melody I heard negroes sing in the South years ago. It is not inserted here with a view to its use in the school-room; it will make an excellent number, however, at a concert or school entertainment. It should have an accompaniment by a banjo or guitar.    S. C. H.

1. I libed wid ole Massa many yeahs ago
Way down on de Tombigbee.
If I ebber gits dar I'll nebber leab again
Till def comes along for me.

CHORUS: I's a-gwine, you's a-gwine, I'se a-gwine back Souf
Whar de sun shines hot, way down whar de sugarcane grows.

2. I'll stick to de hoe till de sun goes down.
I'll rise when de rooster crows.
I's a-gwine back Souf whar de sun shines hot
Way down war de sugarcane grows.

3. I'se hungry now. My feet's a-gittin' col'
An' I trimble when de col' win' blows.
I's a-gwine back Souf whar de sun shines hot
Way down war de sugarcane grows.