p.s. I wrote here about the 3rd vol. of the poem, July, as dominated by speed. The poem exhibits a verbal acceleration analogous to flight (the last phrase of the vol. is "come fly"). The manifestation poem=land (as I described it in previous note) is subject to sort of a time & space warp. This relates back to what I mentioned before about needing, in my own long poem, to distinguish a different sense of time & history from that found in other US long poems. The concept of "Jubilee", for me, is that of a historical-cultural change which takes place as a result of the intervention of an "unspeakable" otherness, which actually folds time and history into a feedback loop. An epiphany. Jubilee, in the poem, is linked to the motif of the ark or "nef" (toy/ritual boat), which reappears in many forms, beginning initially with the "Breugel-Epiphany" section, which opens the 2nd chapter of Stubborn Grew. So the entire poem, Forth of July, could be seen as a mandala, or way-pointer, or icon, of this intervening otherness - analogous to the otherness of poetry itself.
You could say that this speed/flight theme is prefigured in the "Cape Hatteras" section of Crane's Bridge.