The boats they used.

The specific route they traveled to reach this island.

These absences are permanent.

Thirteen thousand years of sediment, sea-level rise, and time have erased them.

What survives is two femora, a suite of radiocarbon dates, a geological context, and the geographic fact that the island existed and the channel existed and the channel required crossing.

A road was eventually built across the land where the Arlington Springs femora spent their long burial — but it is a dirt track used by the ranchers who worked the island before it became a national park, not a highway of continental significance.

The significance lies underground, in the sediment, in the stratigraphy that preserves the record of what happened here at the end of the Ice Age.