And the question it opened — about who the first Americans were, how they arrived, by what routes and in what numbers, and how the diverse peoples of the Americas descended from that founding event — remains one of the most fascinating unresolved questions in the study of human prehistory.

The caves at the edge of Lake Chewaucan are still there, in south-central Oregon, above the dry basin where a great lake used to be.

They have not finished yielding their evidence.

The science has not finished asking its questions.

The people who left those traces 14,000 years ago could not have imagined that their biological waste would one day become evidence in a scientific controversy debated in peer-reviewed journals across the world.

They could not have imagined the laboratories, the radiocarbon accelerators, the genetic sequencers, or the mass spectrometers that would eventually be brought to bear on what they left behind.