Brigid Lynch was surveying a creek for frog habitat when a lumpy, oddly textured object caught her eye. A few photos and a reverse image search later, it was identified as one of the best-preserved mastodon molars the Bay Area has produced. A Frog Survey Turns Up a Mastodon Lynch, a geomorphologist with Balance Hydrologics, was working in a Midpeninsula Regional Open … [Read more...] about A Rock in a California Creek Turned Out to Be an Ice Age Mastodon’s Tooth