Purgatorius by Barry Blumenfeld [not rock pile related]

 "First Human Ancestor Looked Like a Squirrel"
- Discovery News, 19 October 2012

Those who went down in
The cave of Lasceaux
Found a handprint below
A red huge bison
Conforming to the
Wall, but they never
Told us about their
Deeper descent.

Ssshhhhh....

The weeping crags bent
Inward, forcing those
Intruders deeper
Into lightlessness,
Down ladders of rock,
Below every sound,
Into a zone of
The mute, the deaf, and
The dead. They stopped. They
Waited for their eyes
And ears to adjust,
For the ghosts of the
Ancestors to wake
Up. Then water whistled
Over the stones. A
Giant breath was panting....

Ssshhhhh....

Someone–an atheist
Or a Frenchman–
Scratched a match across
His boot. The flame leaped,
And the rocks did too,
And on them in black
Danced squirrels. They
Were tormenting a
Prehistoric cat.
Flames tipped their torches
And burned in their
Ebony eyes. Squirrels
That knew fire and pain!
Their cave-historian
Was proud: below her
Work, she planted a
Blackpaint foot, and her
Long middle claw
Pointed at the dying
Animal – a
Boast, or a warning.
Around the killing
Place, charcoal leaves had
Settled in mounds, like
Souls of the departed.