These materials had their own ceremonial significance and their own practical applications.

If the value of cave gypsum was partly exotic — partly derived from the difficulty of obtaining it, the unusual environment in which it formed, the labor required to collect it — then the advent of materials that were equally exotic and perhaps more visually impressive might have reduced the demand for cave minerals.

Another hypothesis: the communities that had conducted the mining simply moved.

Population shifts in the Eastern woodlands during this period were real, and if the specific communities with knowledge of the cave routes relocated outside the Green River valley, the mining operation would have lapsed.