Do the Indian tales refer to the earth as ***they ***knew it, or as we know it ? An American Indian tale, even if it preserves memories of what is now Siberia, is unlikely to include the Faroe Islands or the Falklands, or Scotland, or New Zealand, in what its authors know of the world. If it does, then it is too recent to be of any value as evidence of an ancient & truly world-wide flood. It’s vanishingly unlikely that the Hebrews meant to include Scotland, Siberia, or Oceania in what they understood by “the whole earth” either. What Genesis refers to, was probably no more than the sort of inundation that causes misery for Bangladesh every few years; Israel’s world was not very large, even as late as the first century BC. For Ezekiel, the Caucasus - the abode of “Gog” and “Magog” - is the back of beyond; so there is no likelihood that his ancestors centuries earlier had any better idea of the true extent of the earth.
There was no cataclysm - though funnily enough, kataklusmos is the word the Septuagint uses in its translation of Genesis to render Hebrew mabbul, “flood” 
There was no cataclysm in the post’s sense - Genesis says nothing of one, so to posit one, is to read into the text what is not there. Which is unsound as a method. If we do that, then we can read anything else into it that we think we need to, or that we care to - but that leads to not reading the text at all, but only our own fancies
(something Fundamentalism does all the time, which is one of the reasons it is (to put it mildly) an unsatisfactory guide to understanding what the Bible means.
Fundamentalism doesn’t interpret the text - it makes connections between the text OTOH, & ways of avoiding any appearance of error in the text OTO. But it displays a callous disregard for the text as such: without knowing what that text is we cannot know what that part of the book - or of any book, Biblical or not - is saying. If Fundamentalism got to grips with the text, it would not be Fundamentalist; it would be listening to what the texts have to say, as the critics do. The Bible is too valuable to be abandoned to the excruciating tortures the Fundamentalists make it suffer; it needs to be rescued from the numberless torments they inflict upon it.
BTW - an ar
c is a line in mathematics (IIRC
) ; the boaty thing people have in mind is an ar
k. And while “Magnum” was a highly watchable TV series, Cro-Magnon man is unlikely to have watched it (or even to have drunken a magnum of wine)
- arc = a curve
- Noah’s ar**k **= tebah in Hebrew
- The ark of the covenant = aron
- the “boat” of the infant Moses = tebah
Hope that helps
? It could be read that way