Late Pleistocene, North America, ca. 11,000 B.P.

There must be some moment
when a thing becomes un-ordinary—bent,

maybe suddenly, out of the commonplace.
Ordinary anything: love, faces, your own face,

piano concerti, politicians, trees,
little buildings, or the masonry

of the Laurentide ice sheet, when its infinitesimal
bricks, each a single crystal

mortared with cold, reached a level
of fifty feet. Or maybe later, when the mantle

under Canada was sagging below
the old seashore lines from the weight of snow

and that same ice wall, sheer-fronted,
stood two and a half miles high—blunt-

topped but sloping gradually
westward from its three-

mile height at Hudson Bay. Dawn light
every day would shoot a straight

line across a continuous cliff
from Greenland west to the midriff

of the continent. Rivers south
of Canada ran northward then, without

much incident, for hundreds of miles. But
a moment would arrive, or an identical set

of moments, when the rivers’ gray
and white chutes, in a piled-up melee

—rolling down the side
of the Appalachian plateau as if on a slide—

ran full force into the base of the ice, and,
with nowhere to turn, had to bend

beneath themselves, churning up gravel
and mud with currents that dug like sandhog shovels.

Forested terrain throughout the Midwest rumbled
like a factory floor while major rivers stumbled

deeper, to six hundred feet down
at some places—self-confluencing, to drown,

channels gone without a trace, self-poured
into what would be the steep-shored

buckets of five inland lakes. However: those
moments were abundant and unclosed,

so it might still have been ordinary, the smash
of waters that climbed as a splash

up the ice wall to half a mile high,
unchanging, for forty centuries: There was high,

unwavering fog; day and night,
the same pitch to the roar and the same slight

Doppler shift—registered by a deer,
white-tailed, sprinting from a gray wolf near

the shore, crouching amid aspen and everyday
pines. White and gray

mornings were followed by
white and gray afternoons, every

moment of which a paralyzed
rainbow arched above icebergs the size

of small towns. No doubt
even the guano quantity stayed about

the same on shelves of slow-bobbing
iceberg chunks, where the mobbing

grebes and mergansers flew out
to fish for the fry of pike and trout,

alongside gulls by the thousands. Geese
kept scouting the ice-filigreed weeds;

there were beaver, otter, mice—species too numerous
to be remarkable but not over-numerous

enough for briefly enough to be remarkable,
either. The gulls’ cries, already stable

for forty million years before the Pleistocene,
were not more soft or raucous then

than if their icy cliff had been
a ledge of just ten

inches—the same gull species patrolling now
in short swoops or shouting in crowds

every afternoon
from the piers on Lake Michigan,

in the usual haze: commonplace, sort of, in a way,
in their as-yet-unchanged white and gray.

____

With the retreat of the glaciers and the rebounding uplift of the North American continent—which tilts now to the south—no major river in the U.S. empties to the north.