Makapansgat Pebble

I've just learned about this thing called the Makapansgat Pebble. It was believed to have been carried by a protohuman, the earliest example of such a thing (the Australopithecine remains accompanying it are in the area of two to three million years ago). The term for such an object - out of natural place, and believed to have been transported and deposited by hominids.

Here's a picture of it:



I learned about it from Dinosaur Comics. You can probably learn more at Wikipedia or Google.