Upon the floor of light, and time, Unmurmuring, of polyp made, We rest; we are, as light withdraws, Twin atolls on a shelf of shade.
Is your neck sore yet from looking up, then looking down? Now the speaker tells us that they ("we") are resting "upon the floor of light and time"—sounds comfy, right?
"Unmurmuring" echoes (if silence in this case can be said to make a sound—and it does) the "nameless motions" in line 8. Just take a look at how many words in this poem have "un" or "less" attached to them. In this way, the poet can plant the idea of something in the same moment that he plucks it away. "We" (the subject of "Unmurmuring," which is hanging out in the line below) are quiet now, but the implication is that maybe "we" were making some noise moments ago (wink, wink).
Something else you should know: we are, the speaker says, "of polyp made." Come again? Did he just say "polyp"? Can you imagine a less poetic word? It's hard not to think of those abnormal growth thingies that some people (hopefully nobody you know) get in their colons. T.M.I., right? Why would a so-called wordsmith include such an unfortunate, yucky word?
Well, there's another meaning of "polyp": a small organism that, together with a bunch of its friends, makes up coral. This might make a lot more sense, given the whole marine theme.
So why didn't Warren just say, "We are of coral made"? Wouldn't that be a lot prettier? (Um, yeah). Clearly, he wants there to be a little tumor-like idea growing somewhere in this poem. Something may be rotten in amidst all this dreamy, watery serenity.
We're back in the water, though, when the speaker compares himself—and whoever he's with—to "twin atolls," which are strings of islands made from coral (yup, those groups of undersea polyps), as the "tide" of light recedes (think sunset) and leaves them in shade.
More specifically, an atoll is an island surrounded by a lagoon of water. The water would be the air and the darkness, that "shelf of shade." Nice alliteration, Red. (Check out "Sound Check" for more on how, and why, this poem uses sound.)
And just what are these islands up to? Well, we're told here that they "are." Of course they are. They're in this poem, aren't they? Why does Warren feel the need to make this activity specifically known? Such statements ring a bell to signal the theme of existence. As things get darker, the lovers are resting, and being.
One last form note before we head off to the next stanza: though, "made" and "shade" rhyme, but "time" and "withdraws" aren't even close. Hit up "Form and Meter" for more on why that might be.