The radiocarbon dating of the bone proteins and the associated materials produced a strong case for the terminal Pleistocene age of the Arlington Springs individual.

But radiocarbon dates alone do not constitute the full evidentiary picture, particularly for a site as geologically complex as Arlington Canyon.

Returning to the canyon to understand the original depositional context of the bones was essential.

The bones themselves had been removed in 1959-60 and were in museum storage.

The stratum from which they had eroded was what remained in the field, and that stratum needed to be precisely relocated, mapped, and dated independently.

This work involved collaboration between Johnson and a team of geologists who conducted detailed chronostratigraphic work at Arlington Springs — re-identifying the specific sedimentary unit that contained the bones by its lithological characteristics and its relationship to overlying and underlying strata, and independently dating materials from that unit using both radiocarbon and other methods.