Finger Paint

Oh, I like it!

Grammar and sentence structure.

I remember: it was either yesterday
or eternities ago

My opinion is that "eternity" should rarely be made plural. I think you would be better off saying, "...or an eternity ago..."

our own likening.

Is the word not "likeness"? Also, you switch from third person to first person here. It is "their cave drawings"...should it not also be "their own likeness"? I realize that you're trying to make a connection between the old "them" and the modern "us" but it just doesn't flow here.

Man’s own attempted chronicle

This certainly isn't proper. It ought to be "It is" or "It was" man's own attempted chronicle. Of course, that doesn't sound as good, yet this sounds wrong, so maybe you ought to rephrase?

Now, we have fourteen lines divided into only two sentences. Mix it up a little.

Description. I find it unnecessary to describe the drawings as "cave drawings" and their minds as "primal".
"Cave drawings" is unnecessary because cave paintings naturally come to mind when you're describing ancient man; there's no need to blurt it out. You might put the drawings on "stone" or find another way to show that they were the work of the first humans.
Again, we know we're talking about ancient humans, so primal seems unnecessary. You could describe the minds as "early" or "growing" or "archaic" but "primal" just seems out-of-place.

Also:

Man’s own attempted chronicle,
as if something
in their primal minds rebelled against
the world’s forgetfulness

I actually think this could just be shortened to:
Man's own attempted chronicle
as in something
in them rebelled against
the world's forgetfulness.
I really like the part about "the world's forgetfulness." It speaks volumes.

to which all things fade.

This seems like such a weak, vague ending to me, almost like you couldn't think of anything good to put there, and had to settle for this (oh, do I know the feeling).

Lovely!
-Colleen

I remember: it was either yesterday
or eternities ago,

this is a good poetic line, but I hate it because "yesterday" and "eternity" have such a BIG gap that this seems... foolish? It's a good thing but it irks me.

This poem is OK, I think I'm just struggling over whether I like the idea or not...I can't really comment on how it was written, since it wasn't horribly bad or anything. ^_~

Sorry, I seem to be no help.

It was good. The only thing that really bothered me was this part:

as if something
in their primal minds rebelled against
the world’s forgetfulness,

It seems awkwardly broken. To me, it seems smoother if it were just two lines instead of three, such as:

as if something in their primal minds
rebelled against the world’s forgetfulness,

Putting it back with the rest of the poem, it doesn't really stick out, and it does appear to flow better. Change it if you agree. If not, I won't be too broken up *tear*.

Great job.