Traditional about a jealous lover who lures his sweetheart (sometimes named Pearl Bryan(t), sometimes Florella) down into the valley and plunges a knife into her and kills her. The storyline follows the same one found in Pretty Polly and arguably this could be considered as a variant that doesn't warrant adaptation status.
[Verse One of the Lone Green Valley variant] Way down in a lone green valley down where the roses bloom and fade, There was a jealous lover in love with a beautiful maid.