Here is one of the most important implications of the Manis discovery: the archaeological record of the first Americans is profoundly biased toward stone.

Stone tools survive almost indefinitely in almost any burial environment.

Stone does not rot, does not dissolve in normal groundwater chemistry, and does not break down under the biological activity that destroys organic material.

A stone spear point buried fourteen thousand years ago will still be there today, recoverable by any excavation that reaches the right level.

Bone, by contrast, is organic.

It survives only under specific conditions: frozen ground, extremely dry conditions (like the Nevada cave that preserved the Spirit Cave Man), underwater sites with specific chemistry, or other unusual preservation environments.