Earth Science Club of Northern Illinois

Mazon Monday #343: 1990 Mazon Creek Open House

The Mazon Creek Open House was first held in early 1984. It was an extension of the Mazon Creek Project at Northeastern Illinois University. Both the Mazon Creek Project (see Mazon Monday #5) were sponsored by Northeastern Illinois University.

Around the Web

Found On Newcastle Ranch, ‘Rex Jr.’ Could Be Most Important T. Rex Ever Discovered

Cowboy State Daily has a story about “Rex Junior.” First discovered in the 1950’s on a ranch near Newcastle, Wyoming, a partial skeleton of a sub-adult T. rex may be the most important T. rex that has or will ever be found. That is the opinion of paleontologist Paul Sereno. Sereno said “this specimen from the newly discovered mummy zone will redefine what we know about T. rex, inside and out.” Sereno encountered Rex Junior at the top of a hill near Newcastle in the 1990s. It eroded out of the Lance Formation, a 67-million-year-old layer of rock dating to…

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Sternberg Museum in Hays to close by year’s end

More horrible museum news… this time the Sternberg Museum in Hays, Kansas. See the story at KWCH News 12. The fundraising campaign started by the Fort Hays State University Foundation can be found here. HAYS, Kan. (KWCH) – The Sternberg Museum in Hays will be closing before the end of the year. The President of Fort Hays State University, Tisa Mason, shared a statement with the school sharing details on the decision to close the historic museum. The statement shares that the public-facing operations of the Sternberg Museum will close on Dec. 18 as part of the university’s Strategic Budget…

Fossil Friday, Mazon Creek

Fossil Friday #337: A Different View of Lepidostrobus

Lepidostrobus is a cone from lepidodendron tree. It was named in 1828 by Adolphe-Theodore Brongniart (1801 – 1876), who was a French paleontologist, considered by many to be the father of paleobotany. He also named Lepidostrobophyllum which are the individual cone bracts of which Lepidostrobus is the whole reproductive organ. See Mazon Monday #202.

Calendar of Events

ESCONI Events for October 2026

Field trips require membership, but visitors are welcome at all meetings! Friday, October 9th General Meeting – 8:00 PM via Zoom. Lazaro Vinola from The Field Museum will be presenting live from the field in the Dominican Republic. Saturday, October 10th Junior Study Group Meeting – 2:00 PM at College of DuPage, TEC, Room 1038A Earthquakes! Junior members will watch videos about earthquakes, make seismographs and test them. Specifics of this meeting are available from Scott Galloway, 630-670-2591, gallowayscottf@gmail.com. Saturday, October 10th Mazon Creek Fossil Day Details are here. Saturday, October 17th Field Trip to Danville for Carboniferous Fossils Details…

Mazon Creek, Throwback Thursday

Throwback Thursday #337: Looking Back At ESCONI for October 2026

ESCONI highlights from 25, 50, and 70 years ago

Calendar of Events, Mazon Creek

Reminder: Mazon Creek Fossil Day 2026 – Saturday, October 10th, 2026 – Coal City Library

The 2026 Mazon Creek Fossil Day will be held on Saturday, October 10th, 2026 at the Coal City Library from 10 AM to 3 PM. See you there! Previous events

Around the Web

T. Rex, King of the Dinosaurs, Had a Body Temperature of 97 Degrees

The New York Times has a story about recent T. rex research. There’s been a long running debate about whether dinosaurs were warm or cold blooded – endothermic or exothermic. New research, published recently in the journal Science Advances, adds a little evidence to the warm blooded side. Scientists at the University of California, Los Angeles, used a geochemistry techniques on fossilized teeth, including two from “Thomas”, a T. rex at the National History Museum of Los Angeles County. They looked at carbon and oxygen bonds in a the T. rex teeth. Bonds of the heavier isotopes act as a…

Mazon Creek, Mazon Monday

Mazon Monday #342: Jeanerpeton mazonensis – A new Mazon Creek tetrapod!

The Mazon Creek fossil biota has a new member… a tetrapod, which are quite rare. Jeanerpeton mazonensis, which means “Jean’s crawler from Mazon Creek”, was named by two student-scientists from the Field Museum. The name honors their mothers, who are both named Jean.

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A strange circle on satellite maps turned out to be a 390-million-year-old impact crater

Science Daily has a story about a recently discovered impact crater. The crater was hidden in the Quebec wilderness near Lake Marsal in eastern Quebec. The impact that formed the crater dates to about 390 million years ago during the Devonian Period. It was found by an amateur astronomer, who noticed the structure while planning a camping trip in 2024. In 2024, Joël Lapointe was preparing for a trip to the remote Côte-Nord region when a circular feature near Lake Marsal caught his attention on online satellite imagery. He wondered whether the depression could have been formed by an impact…

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A Feather Found in Dinosaur Poop Might Explain How Birds Beat Extinction

The New York Times has a story about an amazing, chance discovery. In 2016, a researcher in the Hell Creek Formation in Montana picked up a small rock that turned out to be a small piece of fossilized dinosaur dung. Fossilized dung is called a coprolite and this one had a “big” surprise. It had broke in half and revealed a tiny, well-preserved feather alongside fragments of avian bones. This was likely the leftovers from a bird’s final meal before being eaten. An extremely well-preserved bird feather from the age of dinosaurs has been found inside a fossilized piece of…

Fossil Friday, Mazon Creek

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.

Throwback Thursday

Throwback Thursday #336: Vacation Trip to Oregon

The 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.

Calendar of Events

Recap of the ESCONI “Brag Night” 2026

ESCONI 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!

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! ⁠

Mazon Creek, Mazon Monday

Mazon Monday #341: Titanoscorpio douglassi

Titanoscorpio 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!

Around the Web

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.

Around the Web

10,000-year-old fossilized mastodon tooth found in Bay Area creek

ABC 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)…

Fossil Friday, Mazon Creek

Fossil Friday #335: A Couple of Beautiful Rhacophyllum

Long-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!

Throwback Thursday

Throwback Thursday #335: A Look Back At “Brag Night” in the 1960’s

We 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.

Friday, October 9th	General Meeting – 8:00 PM via Zoom. Lazaro Vinola from The Field Museum will be presenting live from the field in the Dominican Republic.
Saturday, October 10th	Junior Study Group Meeting – 2:00 PM at College of DuPage, TEC, Room 1038A Earthquakes! Junior members will watch videos about earthquakes, make seismographs and test them. Specifics of this meeting are available from Scott Galloway, 630-670-2591, gallowayscottf@gmail.com.
Saturday, October 10th	Mazon Creek Fossil Day Details are here.
Saturday, October 17th	Field Trip to Danville for Carboniferous Fossils Details are here.
Saturday, October 17th	Paleontology Study Group – 7:30 PM via Zoom Enrique Clark will be presenting “Depositional and Lithostratigraphic Characterization of the Lower Maysvillian Calloway Creek Formation.”
No meeting this month	Mineralogy Study Group

Mazon Creek Fossil Day – October 10th, 2026!

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