The Fenn Cache: Artifact #111

This Clovis biface—or two-faced point with a continuous edge—is made of Green River Formation chert. Though precisely when the Fenn artifacts were made is unknown, experts used a process known as hydration analysis to get a rough idea of when two obsidian points in the cache were created. When a newly broken piece of obsidian is buried in soil it begins to absorb water, forming a "hydration rind." Experts can use the thickness of this rind to roughly determine age, which in the case of the two obsidian points tested was thousands of years old.