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Fossil Friday #336: Shark Egg Case from Chowder Flats
Read more: Fossil Friday #336: Shark Egg Case from Chowder FlatsHere’s a beautiful Palaeoxyris prendeli from Chowder Flats. It’s a shark egg case thought to have been produced by hybodont sharks. P. prendeli was named by Leo Lesquereux in 1870. At that time, it was believed to be a plant part, maybe a seed pod. The name palaeoxyris comes from the the flowering plant genus Xyris, which grows in swampy environments in the tropics and subtropics. There are a number of species found in India. There, they are commonly known as yellow-eyed grasses and are characterized by their grass-like leaves and yellow iris-like flowers.
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Throwback Thursday #336: Vacation Trip to Oregon
Read more: Throwback Thursday #336: Vacation Trip to OregonThe October 1959 edition of the ESCONI newsletter included this little burb from the newsletter editor, George Darrow, about his vacation to Oregon during the summer of 1959.
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Recap of the ESCONI “Brag Night” 2026
Read more: Recap of the ESCONI “Brag Night” 2026ESCONI held our annual “Brag Night” 2026 on September 19th, 2026. 20 members braved the torrential rains to share fossils (and a few minerals) with their fellow members. Here’s a quick photo recap…
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PBS Eons at the Field Museum!
Read more: PBS Eons at the Field Museum!View this post on Instagram A post shared by Eons (@eonsshow) PBS Eons posted this video a few days ago on Instagram. In making Life and Death on Pangea, not only did we get to tell the story of one of the most dramatic times in Earth’s history, but we got visit places that were dreams come true for our natural-history-loving hearts!
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Mazon Monday #341: Titanoscorpio douglassi
Read more: Mazon Monday #341: Titanoscorpio douglassiTitanoscorpio douglassi is known from just three specimens, but the holotype is a breathtaking three-inch claw on display at the Prehistoric Life Museum in the basement of Dave’s Down to Earth Rock Shop (see Throwback Thursday #94) in Evanston, Illinois. And yes, it really is breathtaking!
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PBS Eons: Did the Ozone Collapse 252 Million Years Ago?
Read more: PBS Eons: Did the Ozone Collapse 252 Million Years Ago?PBS Eons has a new video. This is another one about the Great Dying about 252 million years ago. What was it about the Great Dying that caused a global age of mutant plants? And could figuring it out help us avoid triggering the next one? Watch Eons: Life and Death on Pangea on the free PBS App: https://to.pbs.org/EonsApp or on the web here: https://pbs.org/eons ← use this link if you are outside of the U.S.
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10,000-year-old fossilized mastodon tooth found in Bay Area creek
Read more: 10,000-year-old fossilized mastodon tooth found in Bay Area creekABC Eyewitness News has a story about an “exceptionally preserved fossilized tooth.” The tooth of an American mastodon was found in a creek in California’s Bay Area. It was found by a scientist doing a survey for an environmental restoration project. The fossil may be more than 10,000 years old. A fossilized Pacific mastodon tooth that scientists say is at least 10,000 years old and in “immaculate condition” was discovered recently in a creek bed in California, according to local officials. The “exceptionally preserved fossilized tooth” was discovered during field surveys for a habitat enhancement project in a Midpeninsula (Midpen)…
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Fossil Friday #335: A Couple of Beautiful Rhacophyllum
Read more: Fossil Friday #335: A Couple of Beautiful RhacophyllumLong-time member Marty Houdek recently sent me a couple photos of Rhacophyllum from Mazon Creek. The first one is a sweet Rhacophyllum clarkii (see Mazon Creek #170), from one of the Braidwood pits (2, 3, or maybe 4?). It’s beautiful. It opened this past summer via freeze/thaw… after being collected 30 years ago!
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Throwback Thursday #335: A Look Back At “Brag Night” in the 1960’s
Read more: Throwback Thursday #335: A Look Back At “Brag Night” in the 1960’sWe hope you’ll come out to “Brag Night” this Saturday, September 19th, 2026! We are sure there will be some very nice treasures to see! “Brag Night” on the first meeting after summer vacation has been an ESCONI tradition for a long time. The first one seems to be 1952. Here is the announcement.
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ESCONI Field Trip to Danville Shale Pile Fossils – Saturday, October 17th, 2026
Read more: ESCONI Field Trip to Danville Shale Pile Fossils – Saturday, October 17th, 2026Danville Field Trip Rules for Saturday, October 17th, 2026 An ESCONI field trip to the Danville, IL Shale Pile for Pennsylvanian fossils is scheduled for Saturday October 17th, 2026 starting at 10 AM. This is on private property and there is an attendance limit of 25 people. The gate will be secured once we are in and locked when we leave. Plan on being off the hill at 3 PM to give time for specimen identification and pictures. You must register to go on this trip. See rule 6 below for instructions. This is the only way to register. Those…
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ESCONI “Brag Night” 2026 – Saturday, September 19th, 2026 at 7:30 PM at the College of DuPage, TEC 1038B
Read more: ESCONI “Brag Night” 2026 – Saturday, September 19th, 2026 at 7:30 PM at the College of DuPage, TEC 1038BCome on out and show off your finds for 2026! “Brag Night” has been a ESCONI tradition since the very beginning!
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Mazon Creek #340: Neuropteris thompsoniana
Read more: Mazon Creek #340: Neuropteris thompsonianaThis is Mazon Monday post #340. What’s your favorite Mazon Creek fossil? Tell us at esconi.info@gmail.com. Neuropteris thompsoniana was described by William Culp Darrah (1909-1989), in 1969. Darrah was an American professor of biology at Gettysburg College, in Pennsylvania. He was a specialist in paleobotany. In addition to paleontology, Darrah had a deep interest in 19th century photography, and published several works on the subject. His daughter, Elsie, wrote and edited book “Historical Perspective on Early Twentieth Century Carboniferous Paleobotany in North American”, which was dedicated as a memorial volume to her father. N. thompsoniana is a very rare variety of Neuropteris. It is…
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PBS Eons: Why Were Sails So Popular 300 Million Years Ago
Read more: PBS Eons: Why Were Sails So Popular 300 Million Years AgoPBS Eons has a new video. This one is about a time when many animals had sails. This is a tale about sails, and the enigma of why, for a brief but critical phase in the history of life, sporting a big biological billboard was all the rage.
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The World’s First Bugs Had Way More Legs
Read more: The World’s First Bugs Had Way More LegsThe New York Times has an interesting article about research that has uncovered an early insect. The animal, Chosha praecursor, lived about 324 million years ago during the Carboniferous Period in what is now Texas. It looked very similar to modern day silverfish, with a huge difference… it had 24 legs! C. praecursor was described in the paper “Amphibious stem-insect sheds light on colonization of land”, which was published in Nature. Erik Tihelka’s first glimpse of one of the world’s oldest insects came from an outdated Russian textbook that he bought on eBay. In it, a small line drawing of…
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Fossil Friday #334: Mariopteris from Pit 4
Read more: Fossil Friday #334: Mariopteris from Pit 4I was talking to Ralph Jewell and Jeremy Zimmerman at the Braceville field trip a few weeks ago and they showed me a very nice fern fossil. Make that a seed fern… it seems to be a variety of Mariopteris, maybe Mariopteris decipens (see Mazon Monday #108) or the much rarer Mariopteris wilmingtonenese (see Mazon Monday #211). What do you think? Let’s hear your thoughts…
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Throwback Thursday #334: Gorgeous George in 1976
Read more: Throwback Thursday #334: Gorgeous George in 1976This is “Gorgeous George”, when he was on display in the main gallery in 1976. He and the Lambeosaurus were star attractions at the museum from 1956 to 1992. He was incorrectly called a Gorgosaurus for most of its “life”. That was corrected in 1999 and he is now known as a Daspletosaurus, a rare species of tyrannosaur. “George” originally hailed from Alberta, Canada and was found by none other than Barnum Brown of the American Museum of Natural History (AMNH).
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ESCONI September 2026 General Meeting, Friday, September 11th, 2026 at 8:00 PM via Zoom – “Searching for Colorado’s Tiktaalik on the West Coast of Laurentia”
Read more: ESCONI September 2026 General Meeting, Friday, September 11th, 2026 at 8:00 PM via Zoom – “Searching for Colorado’s Tiktaalik on the West Coast of Laurentia”The September 2026 General Meeting will be held on Friday, September 11th, 2026 at 8:00 PM via Zoom. Our presentation is by Franklin Duffy, PhD Student and Research Affiliate from The Field Museum and Denver Museum of Nature & Science. He will be presenting “Searching for Colorado’s Tiktaalik on the West Coast of Laurentia.” This presentation is a spotlight on our fieldwork in the Late Devonian Parting Formation of Colorado and the transitional “fishapod” fossils that can be found there. This talk will be a deep dive into why the timing, depositional environment and fossil taxa suggest that this is…
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What Did Jurassic Forests Sound Like? Like This.
Read more: What Did Jurassic Forests Sound Like? Like This.The New York Times has an interesting story about the sounds of Jurassic forests. Insect chirps, trills, and clicks make up a large part of the Earth’s modern soundscape. Recently, a group of researchers looked at fossilized insect wings from the Jurassic to determine the sounds they’d make 150 million years ago. The research paper was published in the Proceedings of the National Academy of Sciences. This buzzy chorus contains the calls of nine species of prehistoric insects that an international team of scientists spent more than a decade reconstructing. The insects, which are the relatives of modern-day crickets and…
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Mazon Monday #339: Braceville Fall 2026 Field Trip Report
Read more: Mazon Monday #339: Braceville Fall 2026 Field Trip ReportAt the end of August, ESCONI held our annual Fall field trip to the Braceville Spoil Pile, known as “Worm Hill.” It was a huge success. The weather cooperated for the most part. Saturday, August 29th was a beautiful day, with no rain and highs in the mid-70’s. Unfortunately, Saturday, August 30th started out with rain, but that slowed and stopped by about 10 AM. The ground soaked up most of the water and some of the shale was softened for our ready picks and shovels.
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A Nearly 200-Year-Old Museum Known for Its T. Rex Faces Extinction
Read more: A Nearly 200-Year-Old Museum Known for Its T. Rex Faces ExtinctionThe New York Times has a piece about the plight of the Academy of Natural Sciences in Philadelphia. The institution first opened its door in 1828… nearly 200 years ago. It is the oldest natural history museum in the US. Due to financial difficulties since the Covid-19 pandemic, it is being forced to close at the end of September. At the end of September, the facility known for its Dinosaur Hall and its extensive collection of fossils and other specimens will permanently close, a casualty of struggling attendance and rising costs, the academy and the university said in a joint message on Tuesday. The message…
Mazon Creek Fossil Day – October 10th, 2026!
Most Recent Post
- Fossil Friday #336: Shark Egg Case from Chowder Flats
Here’s a beautiful Palaeoxyris prendeli from Chowder Flats. It’s a shark egg case thought to have been produced by hybodont sharks. P. prendeli was named by Leo Lesquereux in 1870. At that time, it was believed to be a plant part, maybe a seed pod. The name palaeoxyris comes from the the flowering plant genus Xyris, which grows in swampy environments in the tropics and subtropics. There are a number of species found in India. There, they are commonly known as yellow-eyed grasses and are characterized by their grass-like leaves and yellow iris-like flowers.
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Field trips require membership, but visitors are welcome at all meetings!
| Friday, September 11th | General Meeting – 8:00 PM via Zoom. Franklin Duffy, PhD student and research affiliate from the Field Museum and the Denver Museum of Nature & Science will be presenting “Searching for Colorado’s Tiktaalik on the West Coast of Laurentia.” |
| Saturday, September 12th | Junior Study Group Meeting – 2:00 PM at College of DuPage, TEC, Room 1038A “Volcanoes” Specifics of this meeting are available from Scott Galloway, 630-670-2591, gallowayscottf@gmail.com. |
| Saturday, September 19th | Field Trip to Mount Orab for Ordovician Trilobites Details are here. |
| Saturday, September 19th | Paleontology Study Group – 7:30 PM at College of DuPage, TEC, Room 1038A ESCONI Brag Night! |
| No meeting this month | Mineralogy Study Group |