Episode 158 of the Rock Art Podcast steps beyond rock art to explore “obsidian conveyance systems”—how volcanic glass moved through travel, trade, and social ties, and what that reveals about prehistoric lifeways. Host Dr. Alan Garfinkel is joined by co-host Chris Webster for a conversation on obsidian sourcing, chemical fingerprints, and why big datasets can reconstruct connections even when stratigraphy is mixed. Alan draws from a major post-wildfire cultural project in southern Oregon’s North Umpqua River Basin, where cleared forests exposed dense artifact scatters and a surprising pattern: heavy reliance on obsidian despite sources 100+ miles away, including biface caches dated to around 4,000 years ago.