At this point it appears to me that "Pretty Saro" and its doppelgaenger "At the Foot of Yonder Mountain" are mostly derived from "The Streams of Bunclody." The 1749 date suggested above looks good too. I have read, but so far cannot document, that there is a local tradition that "The Streams of Bunclody" was written from America by an immigrant from County Wicklow and sent back to Ireland. If this immigrant or a son or daughter or someone who had the song from him was among the early European settlers of the Appalachians, the American versions could easily have been adapted from the immigrant's song. On the other hand, while songs passed freely from America to Ireland as well as in the reverse direction, I don't think that this included Appalachian songs, and the ones we are here concerned with are definitely Appalachian/Ozark songs, not traditionally known elsewhere. In this case, 1749 could be the date of the immigrant's arrival in America, although the stanza with the date did not go back to Ireland or was dropped there. Of course, there is a lot of floating lyric here, and John Moulden has some excellent observations on the dangers of taking such material as a basis for identifying oral texts as versions of the same song (I don't have the reference handy, see his edition of Sam Henry's songs). What one must look for is distinctive stanzas; otherwise there would be just one song of which "Pretty Saro," "On Top of Old Smokey," "It was in the Month of January," "The Wagoner's Lad," and countless others would be examples. But these do have distincive content and I think the filiation is that "Streams of Bunclody" begat "Pretty Saro."

Stephen