From sea to shining sea

I'm going to comment on two related arguments for the claim that Scripture teaches a flat earth:

The phrase which he thereby introduces is "from sea to sea" as found in Ps 72:8 and Zech 9:10b, both of which describe the geographically universal rule of the coming Messiah as being "from sea to sea and from the river to the ends of the earth."
The context of these verses which are clearly speaking of the geographically universal rule of the Messiah over all nations on earth (Ps 72:9-11; Zech 9:10b; Cf. Ps 2:8 and Mic 5:4)implies that the phrase "from sea to sea" is a reference to the "two oceans on either side of the world", which enclose within their grasp the entire earth, the two oceans "in the middle of which lies the earth like an island." The phrase "from sea to sea" refers to two specific bodies of water, but not to these bodies of water just in themselves but as representative parts of the "two oceans on either side of the world."
The biblical terms "eastern sea" and "western sea," especially as used in Zech 14:8, where the context is one of apocalyptic universality, also seem to refer to the eastern and western halves of the ocean that surround the earth.
http://faculty.gordon.edu/hu/bi/ted_hildebrandt/otesources/01-genesis/text/articles-books/seely_earthseas_wtj.htm

There are several glaring problems with Seely's argument:

i) His claim is unintentionally comical to American readers. After all, we have a national anthem that locates the continental US "from sea to shining sea." That doesn't imply a mythical cosmography. 

ii) Seely fails to take genre into account. The prophets and psalmists often use poetic imagery. 

iii) Yes, the verses in question refer to the Messiah's global reign, but they do so by using symbolic geography. 

iv) Standard commentaries identify the two seas as the Mediterranean, on the one hand, and the Red Sea, Dead Sea, or Gulf of Aqaba, on the other hand. Those are real bodies of water, not mythical bodies of water. 

On a related note is the claim that when Scripture refers to the "ends of the earth," that presumes a flat-earth cosmology. In this regard, it's instructive to consider a statement by Jesus:

The queen of the South will rise up at the judgment with this generation and condemn it, for she came from the ends of the earth to hear the wisdom of Solomon, and behold, something greater than Solomon is here (Mt 12:42; par. Lk 11:31).

That's illuminating because Jesus attaches a landmark to the stock phrase, where Sheba represents the "ends of the earth." Scholars usually locate Sheba in Yemen. Cf. E. Yamauchi, Africa and the Bible (Baker 2004), 90-91.

Although Yemen occupies the far end of the Arabian peninsula, Yemen is adjacent to Africa–separated by the Red Sea. And Africa extends far below Yemen. I daresay many people living in the Roman Empire knew perfectly that the world (or even dry land) didn't literally come to an end at Yemen. Even in Solomon's time, Jewish mariners were familiar with that part of the world (1 Kgs 9:26-28). They may not have known where Africa bottoms out, but they knew that Yemen doesn't mark the terminus of the S. Hemisphere. So Christ's statement is idiomatic and hyperbolic.