Peter, it looks as though it may have been Paul Robeson. I am finding listings for him singing "Round the bend in the road." IT was on youtube, but it has been removed. Here's a listing:

Paul Robeson, Ol' Man River [X25]
    CD only
    Availability: Rediscover Music Catalog (Catalog # PRO7839D)

          Contents:
                Roll Away Clouds;   Lonesome Road;   Got the South in my Soul;   Hush-a-Bye Lullaby;   Round the Bend of the Road;   Cary Me Back to Green Pastures;   Blue Prelude;   Wagon Wheels;   So Shy;   St. Louis Blues;   Little man, You've Had a Busy Day;   I Ain't Lazy, I'm just Dreaming;   Shenandoah;   All Through the Night;   Solitude;   Song of the Volga Boatmen;   Dear Old Southland;   Nothin';   A Perfect Day   

I'll see if I can find an audio.