[Talisker]

Twas a comet, struck Camelot on Wales and destroyed it, and sent King Arthur to Kentucky.

No, I'm not kidding.

King Arthur II sailed to America, was killed in Kentucky, buried in Wales

[SunkenCiv]

Arthur’s Comet?

[blam]

"Twas a comet, struck Camelot on Wales and destroyed it, and sent King Arthur to Kentucky. "

(Prince) Madoc In America

[gleeaikin]

There are some interesting stories about the Mandan Indians which may relate to this. I think someone on the Lewis and Clarke expedition had a Welsh speaker who commented on linguistic similarities, and they also had a different cultural organization than other Indians.