As others have pointed out above, this song and "I'll Lay Ye Doon, Love" are creative reworkings of what are often termed 'Stage Irish' pieces - popular songs written for the music hall and published in sheet music and broadside form. "I'll Lay Ye Doon, Love" came from the piece "Muldoon, The Solid Man", and "Jock Stewart" from "I'm The/A Man You Don't Meet Every Day". New York seems to have been a locus for the stage Irish phenomenon. It's worth pointing out that there's a similar phenomenon with Harry Lauder and other Scottish music hall piece ending up reworked by Scots Travellers as well.