Yes, this site is roughly 13,900 years old.

Yes, the foreign bone inside the rib was eventually identified as a human-made projectile point.

Yes, that implies people were hunting mastodon on the Pacific Coast of North America well before the traditionally accepted earliest-Americans timeline.

But the story of how scientists got from a strange object inside a rib to that conclusion — and why it took so long, and why it required so much technology — is the actual story worth telling.

It is a forensic case from the Ice Age, conducted across four decades, with the evidence locked inside a piece of bone the size of a human forearm.

A Mastodon Beneath Washington Soil

The Olympic Peninsula is a distinctive place.

Bounded on the west by the Pacific Ocean, on the north by the Strait of Juan de Fuca, and dominated inland by the Olympic Mountains — one of the wettest ranges in the contiguous United States, fed by Pacific storms that drop extraordinary amounts of rain on the western slopes — it is a landscape defined by its extremes of moisture, topography, and biological abundance.

Today, it supports some of the most productive temperate rainforest in the world.

The Hoh Rain Forest, on the park’s western side, receives between twelve and fourteen feet of precipitation per year.

The trees — Sitka spruce, western red cedar, big-leaf maple draped in moss — reach dimensions that require multiple people to encircle them with outstretched arms.

But the Olympic Peninsula of 13,900 years ago was a different world.

The great ice sheets that had covered much of northern North America during the Last Glacial Maximum had retreated significantly by this point, and the Pacific Northwest was experiencing the climatic and ecological transition of the late Pleistocene — the period just before the Ice Age ended, when landscapes were being reorganized, sea levels were still substantially lower than today, and the mix of plants and animals that occupied the region did not correspond to anything in the modern Pacific Northwest.

Mastodons were part of that world.