While surveying a California creek for threatened red-legged frogs, a scientist spotted what looked like a rock; it was an intact mastodon molar estimated to be 10,000 years old

• Scientist finds 10,000-year-old mastodon molar while surveying California creek for threatened frogs (Image Credit: Balance Hydrologics)A routine field survey in a California redwood forest has led to an extraordinary glimpse into the Ice Age.
• A scientist searching a San Mateo County creek for signs of habitat conditions for threatened California red-legged frogs spotted an oddly shaped object that initially appeared to be an ordinary rock.
• Instead, it turned out to be a remarkably well-preserved tooth belonging to an extinct Pacific mastodon.