Geomorphologist finds rare Ice Age mastodon molar in Bay Area creek
A field survey for threatened red-legged frogs turned up an exceptionally preserved Pacific mastodon tooth in a San Mateo County preserve.
What to know
- A geomorphologist surveying for threatened red-legged frogs accidentally found an exceptionally preserved Pacific mastodon molar in a San Mateo County creek.
- The tooth is described by a paleontologist as the most complete mastodon molar found in the Bay Area.
- The fossil has been donated to Stanford's Doerr School of Sustainability, where researchers plan carbon dating to determine its age, the mastodon's diet, and local Ice Age climate.
- The land managers are not disclosing the exact creek or preserve to prevent unauthorized digging for more fossils.
“This find highlights for me that the presence of mastodons wasn't that long ago, in geologic time. That mastodons were out here in the same landscape that I'm in today, 11,000 years ago roughly, really drives home how important the work we do is to keep species from winking out forever.”
Matt Sharp Chaney, Biologist, Midpeninsula Regional Open Space District · NY Post ↗ · Sep 8
Brigid Lynch Geomorphologist, Balance HydrologicsWayne Thompson Paleontologist, owner of Pacific PaleontologyRyan McCauley Spokesman, Midpeninsula Regional Open Space DistrictChristine Garcia Curator, Doerr School of Sustainability specimen collection, StanfordMatt Sharp Chaney Biologist, Midpeninsula Regional Open Space District
How it unfolded 1 development · click the chart to see its coverage articlesposts
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LA Times and social accounts extend coverage of the find
The Los Angeles Times ran its own account of the discovery, and Midpen's social channels shared details of the Pacific mastodon species and its Ice Age ecosystem alongside the fossil news.
“It really stuck out. I had no idea what it was. I thought maybe it was a mollusk or something, but that didn't make sense since it wasn't near the ocean.”
— Brigid Lynch, Geomorphologist who found the tooth · source -
first by LA Times, 13d ago · also PennLive, MassLive, The Oregonian, The New York Times, NYT Science, Smithsonian +2
6 more headlines
- Massive Ice Age-era mastodon tooth found in California creek ktla.com · 13d ago
- Rare Ice Age discovery found in California creek PennLive · 12d ago
- A Mastodon Tooth From the Ice Age Is Discovered in a California Creek The New York Times · 12d ago
- Mastodon tooth found in California creek Mastodon · 12d ago
- A Mastodon Tooth Is Discovered in a California Creek NYT Science · 11d ago
- A Geologist in California Found Something Strange Sticking Out of a Creek. A Reverse Image Search Told Her It Was an Ancient Mastodon Tooth Smithsonian · 8d ago
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first by KXAN Austin, 11d ago · also Yahoo News Canada, AP News, Toronto Star, KCRA, Philadelphia Inquirer, CP24
2 more headlines
- Tooth from another time: Mastodon fossil found in San Francisco creek Yahoo News Canada · 9d ago
- Well-preserved tooth from Pacific mastodon found in a creek in San Francisco Bay Area Phys.org · 8d ago
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A geologist in California who was surveying a San Mateo County creek stumbled upon a preserved Pacific mastodon molar estimated to be at least 10,000 years old.
2 more of the top 3 · 11 posts in this stretch
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In mastodon news today: 10,000-year-old fossilized mastodon tooth discovered in Midpen preserve Fossil discovered in a creek within the forests of San Mateo County https:// msg.openspace.org/mastodon-too th # mastodon # archeology
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Which one of you is this Mastodon tooth found in San Francisco Bay Area https:// apnews.com/article/fossilized- mastodon-tooth-discovery-california-f7acdd7f3a1240ed0710313e2ab87dc8
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background
National outlets pick up the mastodon tooth story — NY Post, Mercury News and SFGate published detailed accounts of the find, quoting paleontologist Wayne Thompson and Midpen spokesman Ryan McCauley, and noting the district is withholding the exact creek location to prevent unauthorized digging.
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Midpen and Stanford announce the discovery and donation — Midpeninsula Regional Open Space District and Stanford's Doerr School of Sustainability released statements describing the find; the tooth was donated to Stanford's collection, where researchers plan carbon dating to determine its age, diet clues and local Ice Age climate conditions.
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Photo search and experts confirm it's a mastodon molar — After running her photo through Google image search at home, Lynch suspected the object was a fossil; colleagues retrieved the tooth from the creek, and Stanford University and paleontologist Wayne Thompson confirmed it as an intact Pacific mastodon molar.
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Lynch spots an odd rock while surveying a creek — Brigid Lynch of Balance Hydrologics, working on a habitat-enhancement survey for the threatened California red-legged frog in a Midpeninsula Regional Open Space District preserve, noticed an unusually shaped, smooth object half-submerged in a creek and photographed it.
Also covered reported alongside — the timeline has no entry for these yet
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first by Yahoo News Canada, 13d ago · also Times of India, Guardian, Guardian Science, ABC News - Breaking News, Latest News and Videos
3 more headlines
- Scientist surveying California creek finds 10,000-year-old mastodon tooth Times of India · 13d ago
- California Scientist Looking for Frogs Finds a 10,000-Year-Old Mastodon Tooth yahoo.com · 11d ago
- Fossilized 10,000-year-old mastodon tooth found by California scientist Guardian US · 11d ago
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first by SFGate Bay Area, 14d ago · also Live Science
1 more headline
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first by The Mercury News, 13d ago · also Mercury News
and 1 smaller piece
What people are saying 8 voices from 1 site · best of 11 · verbatim
- Sep 14
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Mastodon is older than expected! 👏 Let's make it another 10,000 years 👍 https://www. theguardian.com/us-news/2026/s ep/12/fossilized-mastodon-tooth-10000-years-found-california # mastodon # fediverse
- Sep 13
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Ooo Mastadon is mainstream enough for the NY Times! https://www. nytimes.com/2026/09/12/us/ice- age-mastodon-tooth-bay-area.html
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“An exceptionally preserved fossilized tooth belonging to an ancient Pacific mastodon (Mammut pacificus) was recently discovered in a Midpeninsula Regional Open Space District (Midpen) preserve in San Mateo County. The fossil was discovered in a creek bed by geomorphologist Brigid Lynch. What initially appeared to be an oddly shaped rock was later…
- Sep 12
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“A # researcher surveying a San Mateo County creek stumbled upon a preserved Pacific # mastodon # molar estimated to be at least ***10,000*** years old.” https://www. nytimes.com/2026/09/12/us/ice- age-mastodon-tooth-bay-area.html?unlocked_article_code=1.AlE.Czv_.9DNDEv0bDkWd&smid=url-share
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Mastodon. Teeth! TEETH! https://www. theguardian.com/us-news/2026/s ep/12/fossilized-mastodon-tooth-10000-years-found-california
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2/ 'Oddly shaped rock' unearthed in California turns out to be 'immaculate' # mastodon molar https://www. livescience.com/animals/extinc t-species/oddly-shaped-rock-unearthed-in-california-turns-out-to-be-immaculate-mastodon-molar
- Sep 11
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What looked like a rock turned out to be something almost unimaginable https://www. nj.com/news/2026/09/what-looke d-like-a-rock-turned-out-to-be-something-almost-unimaginable.html?utm_source=flipboard&utm_medium=activitypub Posted into New Jersey news @ new-jersey-news-NJcom
- Sep 10
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10,000-year-old fossilized mastodon tooth discovered in Midpen preserve, San Mateo County https:// msg.openspace.org/mastodon-too th