10,000-year-old mastodon tooth found in San Mateo County

A well-preserved fossilized tooth belonging to an ancient Pacific mastodon has been discovered along the peninsula. Geologists say the fully intact adult molar is 10,000 years old. It was recently found in a creek within the forests of the Mid-Peninsula Regional Open Space District Preserve in San Mateo County. Scientists say it initially appeared to be an oddly shaped rock, but was later confirmed to be an ancient tooth. Researchers say they believe Pacific mastodon's range included the areas of what is now California, Oregon, the Rocky Mountains, and parts of Mexico.