After listening for years (in company with my Lewis and Skye mates in our rented Glasgow flat) with enormous pleasure and emotional response to the Gaelic Mass, transmitted every Sunday from Lewis, I now see that this style of singing travelled across to America with Scottish slave masters, where the slaves picked it up (together with the Gaelic language!!)

It didn't. It was a style of church singing found all over Britain in the 16th and 17th centuries, and most of the people who took it to America were English. During the 18th century it was suppressed on the mainland in favour of monophonic styles which made the words more understandable (and allowed for a greater variety of metres and texts), but survived both in the Western Isles of Scotland and in the less developed parts of American South, beyond the influence of musical modernizers. It is not of Gaelic origin.


and it formed the basis of blues!!!

Blues came out of completely different traditions.