This was impact damage — the kind of damage produced when something moving fast strikes something hard enough to drive fragments into and through the target.

Gustafson understood immediately what this implied: a projectile.

Something that had been thrown or thrust with enough force to break through the outer surface of a mastodon’s rib and lodge the broken tip inside the bone.

If that interpretation was correct, the implications were enormous.

A projectile embedded in the rib of an animal dated to the late Pleistocene would be direct physical evidence — not inferred evidence, not indirect evidence, but direct physical evidence — of a human being attacking a mastodon in what is now Washington State at a very specific moment in time.

That was extraordinary.