Call Nancy Grace; there's a poem missing

This month's poetry selection is not really a poem, but the half-remembered fragment of a poem. I came across it a decade ago while at work, and printed it out and memorized as much of it as I could. Now the printout is long gone, and my memory isn't much of a backup system.

The poem, I'm pretty sure, is called "Song on Turning 70." It's by John Hall Wheelock, and even the power of Google has been insufficient to recover the complete work. Guess it's time for a trip to the library. My apologies to readers -- and to the estate of Mr. Wheelock -- for the words and line breaks I have inevitably gotten wrong:

Shall not a man sing as the night comes on?
Great night, hold back
a little longer yet the mountainous black
waters of darkness from this shore,
this island garden, this paradisal spot
the haunt of love and pain
which we must leave, whether we would or not
and where we shall not come again.
More time. Oh, but a little more ...

Does that ring a bell with anyone? I'd love to have the whole poem, but as I say, Google -- which is so diligent about indexing every scabrous blog and bus schedule, doesn't help much with works of poetry. And don't get me started about Wikipedia: Its original entry for John Hall Wheelock cited him as the author of Spoon River Anthology -- which is the best-known work of another favorite poet, Edgar Lee Masters. Be careful when you Wiki, folks.

UPDATE:
The title of the poem is "Song on Reaching Seventy" (italics mine), which may account for why at least a few of my earlier searches came up short. The rest of them -- well, I'm not as smart as I look. Turns out it's helpful to put quotes around the lines you're sure of. Sorry, Google. The poem may be found in The Best Poems of 1957, published by Stanford University Press, and other volumes.

For anyone who cares, here's the entire poem:

Shall not a man sing as the night comes on?
He would be braver than that bird
Which shrieks for terror and is gone
Into the gathering dark, and he has heard
Often, at evening's hush,
Upon some towering sunset bough
A belated thrush
Lift up his heart against the menacing night,
Till silence covered all. Oh, now
Before the coming of a greater night
How bitterly sweet and dear
All things have grown! How shall we bear the brunt,
The fury and joy of every sound and sight,
Now almost cruelly fierce with all delight:
The clouds of dawn that blunt
The spearhead of the sun; the clouds that stand,
Raging with light, around his burial;
The rain-pocked pool
At the wood's edge; a bat's skittering flight
Over the sunset-colored land;
Or, heard toward morning, the cock pheasant's call!
Oh, ever sight and sound
Has meaning now! Now, also, love has laid
Upon us her old chains of tenderness
So that to think of the beloved one,
Love is so great, is to be half afraid --
It is like looking at the sun,
That blinds the eye with truth.
Yet longing remains unstilled,
Age will look into the face of youth
With longing, over a gulf not to be crossed.
Oh, joy that is almost pain, pain that is joy,
Unimaginable to the younger man or boy --
Nothing is quite fulfilled,
Nothing is lost;
But all is multiplied till the heart almost
Aches with its burden: there and here
Become as one, the present and the past;
The dead who were content to lie
Far from us, have consented to draw near --
We are thronged with memories,
Move amid two societies,
And learn at last
The dead are the only ones who never die.

Great night, hold back
A little longer yet your mountainous black
Waters of darkness from this shore,
This island garden, this paradisal spot,
The haunt of love and pain,
Which we must leave, whether we would or not,
And where we shall not come again.
More time -- oh, but a little more,
Till stretched to the limits of being, the taut heart break
Bursting the bonds of breath,
Shattering the wall
Between us and our world, and we awake
Out of the dream of self into the truth of all,
The price for which is death.

JOHN HALL WHEELOCK