A lot of Scottish heather and haggis songs were written in the 50's and 60's - some totally original others (Andy Stewart), often set to pipe tunes or Gaelic airs. The height of vinyl 45's, albums backed by national labels, the last days of popular theatre, radio, and the new TV media taking off - with sheet music still a selling vehicle. The kilted singers.. much of their repertoire written to order, combined with old favourites. My own father wrote a few songs for that market mainly in the 60s-80s period (many currently don't fit the 60 year heading of this thread, more like a 50-year one). Then you had the folk 'revivalists', who also rode on the crest of that cultural wave. American influence really only in the sense of picking up a guitar with the late 50's-60's skiffle and blues boom, and people having a go forming groups.