Another "plantation" connection:

Federal Writers Project guidebook "Savannah" (Savannah: Review Printing Co., 1937), p. 53:

"And so today as the Negro works, he sings that song of by-gone days:

Rollin' John, O Rollin' John
Rollin' John come roll me over
Sally O Gal"

Additionally, in his poem "Poppies and Poinsettias" (1926), the Jamaican-born Claude McKay (1889-1948) writes of

"...music mingling with the toil

"Of half-nude peasants wielding pick and hoe,
Chantying at their labor in the sun:
'Sing Sally-O-Gal-O! Sing Sally-O!'"...

West Indies, plantation labor, "Sing Sally-O!" and "chantying": who could ask for more in three lines?

If only McKay had written a hundred years earlier!