[gumby]

Indeed, these things are complex and incomplete. However I mentioned it as a non-obvious example of how we can be lured into inaccurate interpretations due to our contemporary assumptions.

(by the way I say "inaccurate" but not "wrong" as the point of contemporary reading of classic texts (or any text) is to find insights into your own states, unless you're a historian or historiographer).

[nonbel]

It seems more likely to be a translation issue to me. This is the first I've heard of it but I'd guess "wine-faced" refers to the shimmering surface rather than the color.

Going with "dark" though, Mare Tenebrosum ("Sea of Darkness") was an ancient name for the Atlantic ocean: http://atlantipedia.ie/samples/mare-tenebrosum/