I have seen a couple of videos and other TV stuff on the history of bluegrass that tended to dwell on Irish or Scots origins(or possibly spme weird amalgam called "Irish-Scots", possibly due to the makers being unaware they are different places). One I watched in Ireland last year specifically identified the orign of bluegraa with "Irish-Scots Gaelic culture from the Appalachians meeting black music". Now I would not dispute the huge influence of balack music on bluegrass, but the gaelic bit seems a little strange. Soemhow, if that was true, I feel it would show up more strongly in the surnames of oldtime/bluegrass musicians, and also tune-titles.