And human occupation itself — digging hearths, creating storage features, or simply walking across a sediment surface — can disturb earlier deposits.

The Goldberg et al. critique specifically raised concerns about whether the cave sediments at Paisley showed evidence of the kinds of disturbance that could undermine the stratigraphic integrity of the pre-Clovis layers.

The concerns were not without basis — cave sediments routinely show evidence of multiple types of disturbance, and the complexity of cave depositional processes means that even careful excavation and documentation may not capture all the nuances of how a specific layer formed and was subsequently modified.

Addressing these concerns required more than asserting that the original excavation had been careful.