Also Big Jim, My American husband often compares old Australian rural songs to those from the South-West USA. Both places were settled, (the rural areas anyway) by large groups of men, and only a few women.
Your comment about similarities with the singing style from the Appalatians would have puzzled me a year or so ago. However, I came across a singer on a field recording from Eastern Victoria (Aus) who sang "Barb'ry Allen" in a strikingly similar way. I've never heard it before. I found out that her style came from her Scottish Grandmother. The lady herself was born here. So there you go. Cheers, Joy