Ripples in Time

A couple hundred million years ago
The tide receded for the last time
Leaving ripples in the sand

To the rock, it seems just yesterday
It had been the sand
Gently rolling with the waves

Now, the rock inexorably
Returns to sand
Grain-by-grain

Perhaps in another 200 million years
An ocean will roll in
And ripple the sand again

To the rock, I suppose
This is only so far away
As tomorrow