Coprolites are composed of organic material, and the carbon in that material can be dated directly by radiocarbon methods.

Unlike dating the context around a stone tool — where the tool itself is not datable and the surrounding sediment may have complex relationships to when the tool was deposited — dating a coprolite directly produces an age for the organic material itself.

If that material contains human DNA, the combination of a direct date and a biological identification is extraordinarily powerful evidence.

The Paisley coprolites offered exactly this combination.