Composing a story from clues

I learned the ripples on the surface of a pond analogy for explaining our past from Maturana.  As you toss a pebble into the water, the waves spread out at a standard rate, so that the leaves a, b, and c all move at the same time, and the leaf floating at d moves a little later.  If you have a timer that only looks at the movement of leaves, you could compute where the pebble must have landed. 

If you have time, you may wish to view a one hour episodes of the “The Story of Science”.  The link provided here via tvo is available until Dec. 31, 2014. 

For that matter, if you glance at the pond and see an expanding circle of waves, you just “know” where the disturbance event took place, though you might not know that it was a pebble. 
Only if you keep looking, and see a fish rise to the surface and snatch a floating insect and thus creating a new set of waves can you suggest that the first event might also have been a fish.

What records have persisted from our deep past? 
What are the “leaves” that tell us when something actually happened?