Post Image

Mazon Monday #316: Sublepidophloios protuberans #fossils #paleontology #MazonCreek #MazonMonday #lycopsid #carboniferous #pennsylvanian #illinois

esconi.org/2026/04/mazon-monday-316...

Mazon Monday #315: Another Langford Book Inscription From time to time, we run across some old book inscriptions. Back in Mazon Monday #18, we highlighted a few... Well, here's another interesting inscription.

Mazon Monday #315: Another Langford Book Inscription #fossils #paleontology #history #MazonCreek #MazonMonday

Post Image

Mazon Monday #313: Mazon Creek Studies - the first 120 years #fossils #paleontology #MazonCreek #MazonMonday #history #pennsylvanian #carboniferous #FieldMuseum

esconi.org/2026/03/mazon-monday-313...

Post Image

Mazon Monday #312: Sigillaria tessellata #fossils #paleontology #MazonCreek #MazonMonday #lycopod #lycophyte #pennsylvanian #carboniferous

esconi.org/2026/03/mazon-monday-312...

Post Image

Mazon Monday #311: Strip mining begins in Braidwood on May 23, 1928 #fossils #paleontology #MazonMonday #MazonCreek #coalmining #history #Braidwood

esconi.org/2026/03/mazon-monday-311...

Mazon Monday #310: Cyclus obesus This is Mazon Monday post #310. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Cyclus obesus is one of four species of Cycloidea found in Mazon Creek. It was described in the paper "Mazon Creek Cycloidea" by Frederick Schram. The paper was published in the Journal of Paleontology in 1997. In that paper, Schram established three new species of Cycloidea...

Mazon Monday #310: Cyclus obesus #fossils #paleontology #MazonCreek #MazonMonday #cyclid #Carboniferous #pennsylvanian #cycloidea

Mazon Monday #309: Herbivory is Older Than We Thought! This is Mazon Monday post #309.  What’s your favorite Mazon Creek fossil?  Tell us at  email:esconi.info@gmail.com. The Mann Lab at the Field Museum has been very busy. Their new paper "Carboniferous recumbirostran elucidates the origins of terrestrial herbivory" published in the journal Nature Ecology & Evolution has significant implications for the Mazon Creek ecosystem. This paper shows how even "old" ecosystems like the Sydney Mines and Mazon Creek are constantly being reinterpreted through new discoveries.

Mazon Monday #309: Herbivory is Older Than We Thought! #fossils #paleontology #MazonMonday #MazonCreek #SydneyMines #Canada #Carboniferous #Pennsylvanian #tetrapods

Mazon Monday #308: Acitheca polymorpha This is Mazon Monday post #308.  What’s your favorite Mazon Creek fossil?  Tell us at  email:esconi.info@gmail.com. Fig. 8. Acitheca polymorpha (Brongniart) Schimper; proposed tripinnate-primary frond reconstruction with pinnule type placed at appropriate places. From Taxonomic revision of the Palaeozoic marattialean fern Acitheca" Acitheca polymorpha is an extinct species of the class Filcopsida. It is one of the rarer species of fern found in the Mazon Creek fossil localities.

Mazon Monday #308: Acitheca polymorpha #fossils #paleontology #MazonCreek #MazonMonday #fern #carboniferous #pennsylvanian

Mazon Monday #307: Arjan Mann on Fossil Nerds This is Mazon Monday post #306. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Episode #94 of the Fossil Nerds podcast is "The Marvelous Mini-Monsters of Mazon Creek with Arjan Mann". Arjan is the Assistant Curator of Early Tetrapods at the Field Museum. He discusses his lab's work, various ancient fish and tetrapods, gorganopsids, and (of course!) Mazon Creek.

Mazon Monday #307: Arjan Mann on Fossil Nerds #fossils #paleontology #FieldMuseum #ArjanMann #MazonCreek #MazonMonday #Onychodua #tetrapods

Mazon Monday #306: Drevotella proteana This is Mazon Monday post #306.  What’s your favorite Mazon Creek fossil?  Tell us at  email:esconi.info@gmail.com. Drevotella proteana is believed to be a hydrozoan. It lived during the Pennsylvanian Period. Fossils of this soft-bodied animal are known only from the Mazon Creek fossil deposit, where exceptional preservation allows such delicate organisms to be recorded. Hydrozoans are cnidarians and include jelly-like forms within the subphylum…

Mazon Monday #306: Drevotella proteana #fossils #paleontology #MazonMonday #MazonCreek #hydrozoa #cnidarian

Mazon Monday #305: Herdina mirificus This is Mazon Monday post #305.  What’s your favorite Mazon Creek fossil?  Tell us at  email:esconi.info@gmail.com. Herdina mirificus is an extinct species of short-winged insect, currently classified in the order Protorthoptera. Protorthoptera is an extinct lineage of insects that lived during the middle to late Pennsylvanian Period some 318 to 299 million years ago. The order is a bit of a waste basket, containing a paraphyletic assemblage of basal neoptera.

Mazon Monday #305: Herdina mirificus #fossils #paleontology #MazonCreek #MazonMonday #insects #fossilinsects #carboniferous #pennsykvanian #protorthoptera

Mazon Monday #304: Field Museum… Illinois by the sea This is Mazon Monday post #304.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com. In May 1970, the Field Museum opened an exhibit about Mazon Creek. It was called "Illinois by the sea: a coal age environment" and ran from May 25th until September 25th. It was a successful exhibit that featured Field Museum fossils and contributions from ESCONI members.

Mazon Monday #304: Field Museum... Illinois by the sea #fossils #paleontology #MazonMonday #MazonCreek #carboniferous #pennsylvanian #FieldMuseum

Mazon Monday #303: Smithixerxes juliarum This is Mazon Monday post #303. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Smithixerxes juliarum is among the rarest animals found in the Mazon Creek fossil deposit. It belongs to an extinct group of arthropods known as the euthycarcinoids, which ranged from the Cambrian to the Triassic periods. Some researchers believe euthycarcinoids may have been amphibious, capable of venturing between water and land.

Mazon Monday #303: Smithixerxes juliarum #fossils #paleontology #MazonCreek #MazonMonday #arthropod #Euthycarcinoid #carboniferous #pennsylvanian

Mazon Monday #302: The Wreck of the 5560 This is Mazon Monday post #302.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com. The Marion Power Shovel Company was an American company that designed, manufactured, and built steam shovels, power shovels, blast hole drills, excavators, and dragline excavators. The company was headquartered in Marion, Ohio and operated from 1884 to 1997, when it was acquired by its competitor…

Mazon Monday #302: The Wreck of the 5560 #fossils #paleontology #MazonCreek #MazonMonday #history #coalmining #coal #powershovel

Mazon Monday #301: Cordaianthus ovatus This is Mazon Monday post #301. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Whole-plant reconstruction of Cordaites borassifolius (Sternberg) Unger (reconstruction by J. Svoboda). Cordaianthus ovatus is thought to be the fertile structure for Cordaites borassifolius (see Mazon Monday #299), an extinct genus of early gymnosperms. Cordaites probably grew to more than 100 feet tall in swampy conditions, forming forests similar to modern day mangroves.

Mazon Monday #301: Cordaianthus ovatus #fossils #paleontology #MazonCreek #MazonMonday #Pennsylvanian #carboniferous #gymnosperms #paleobotany

Mazon Monday #300: Mazon Creek horseshoe crab fossil shows evidence of ancient algal or parasitic infestation This is Mazon Monday post #300.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com. The Lauer Foundation just won't let the Mazon Creek horseshoe crabs alone... first it was Euproops danae remains in bromalites (see Mazon Monday #283), now they've found evidence of ancient algal or parasitic infestation in another Euproops danae fossil from the Mazon Creek biota.

Mazon Monday #300: Mazon Creek horseshoe crab fossil shows evidence of ancient algal or parasitic infestation #fossils #paleontology #MazonMonday #MazonCreek #horseshoecrab #Carboniferous #Pennsylvanian

Mazon Monday #299: Cordaites borassifolius This is Mazon Monday post #301. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Whole-plant reconstruction of Cordaites borassifolius (Sternberg) Unger (reconstruction by J. Svoboda). Cordaites borassifolius is an extinct genus of early gymnosperms. Cordaites probably grew maybe 100 feet tall in the drier areas of the Carboniferous swamps. They had stilt-like roots, forming forests similar to modern day mangroves.

Mazon Monday #299: Cordaites borassifolius #fossils #paleontology #MazonCreek #MazonMonday #Pennsylvanian #carboniferous #gymnosperms #paleobotany

Mazon Monday #298: The Freeze/Thaw Method This is Mazon Monday post #298. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. With winter arriving this weekend, it’s the perfect time to set out a few containers of Mazon Creek concretions and let nature do the work. Many collectors take advantage of the season’s freeze/thaw cycles to speed up the opening process, by placing buckets or smaller containers of nodules gathered throughout the year outside to weather naturally in the cold of winter.

Mazon Monday #298: The Freeze/Thaw Method #fossils #paleontology #MazonCreek #MazonMonday #concretions #FieldMuseum #pennsylvanian #carboniferous #history #winter

Mazon Monday #297: Pit 11 Coal Mining Artifact This is Mazon Monday post #297. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. We often focus on the beautiful fossils found in the Mazon Creek deposit, but sometimes overlook the rich history that surrounds them. Coal mining played a central role in shaping the Wilmington, Braidwood, and Coal City area, from the deep shaft mines of the mid-1800s to the massive strip mining operations of the 20th century.

Mazon Monday #297: Pit 11 Coal Mining Artifact #MazonCreek #MazonMonday #pit11 #coal #coalmining #histiory

We often focus on the beautiful fossils found in the Mazon Creek deposit, but sometimes overlook the rich history that surrounds them...

Mazon Monday #296: Jim Turnbull in Pit 11 This is Mazon Monday post #296. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Jim Turnbull, namesake for Anthracomedusa turnbulli (see Mazon Monday #278), worked for Abbott Labs for many years. Abbott has/had an internal newsletter called "AbbotTopics". In the October 8th, 1965 edition, Jim is the subject of an article titled "Prehistoric Insect Discovery May Bear Abbott Man's Name".

Mazon Monday #296: Jim Turnbull in Pit 11 #fossils #paleontology #MazonMonday #MazonCreek #pit11 #history

Mazon Monday #295: Ida Thompson at Pit 11 This is Mazon Monday post #295. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Michele Micetich, curator of the Carbon Hill School Museum, provided the photos in this post. The photos are part of the Tom Testa collection at the museum. On the back of the photos, there are notes written by Ida Thompson to Melbourne McKee, a chemist for the Peabody Coal Company in the Coal City area.

Mazon Monday #295: Ida Thompson at Pit 11 #fossils #paleontology #MazonCreek #MazonMonday #history #pit11

Mazon Monday #294: Montceau-les-Mines This is Mazon Monday post #294. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. A closed coal-washing plant in Montceau-les-Mines (Wikimedia Commons) Montceau-les-Mines is a commune located in the Saône-et-Loire department of the Bourgogne–Franche-Comté region in eastern France. It lies southwest of the city of Dijon and today has a population of just under 20,000 people. The town was officially established on June 24, 1856, from territory taken from several nearby villages — Blanzy, Saint-Vallier, Saint-Berain-sous-Sanvignes, and Sanvignes-les-Mines.

Mazon Monday #294: Montceau-les-Mines #fossils #paleontology #MazonCreek #MazonMonday #France #lagerstatte

Some 303-305 million years ago, during the Carboniferous Period, Central France...

Mazon Monday #293: Mazon Creek Project Slides This is Mazon Monday post #293.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com. Strip Mine Spoil Ridges, Pit 11, Will Co., Illinois. We've all "been there." (Circa 1970) The Mazon Creek Project was a program sponsored by Northeastern Illinois University. Founded in the 1960s, by the late Eugene Richardson Curator of Fossil Invertebrates at the Field Museum in Chicago Illinois.

Mazon Monday #293: Mazon Creek Project Slides #fossils #paleontology #MazonCreek #MazonMonday #history

The Mazon Creek Project was a program sponsored by Northeastern Illinois University. Founded in the 1960s, ...

Mazon Monday #292: Mazon Creek Fossil Day 2025 This is Mazon Monday post #292. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. We had a nice turnout at the Mazon Creek Fossil Day event in the Coal City library a few weeks ago. There were multiple displays by members and people brought in some of their finds for identification. Last week's Fossil Friday was an absolutely beautiful shark egg case (

Mazon Monday #292: Mazon Creek Fossil Day 2025 #fossils #MazonCreek #MazonMonday #paleontology

We had a nice turnout at the Mazon Creek Fossil Day event in the Coal City library a few weeks ago...

Mazon Monday #285: Etacystis communis #fossils #paleontology #MazonMonday #MazonCreek #pennsylvanian #carboniferous

esconiinfo-ehnsm.wpcomstaging.com/2025/09/01/m...

Mazon Monday #284: Mayomyzon pieckoensis #fossils #paleontology #MazonMonday #MazonCreek #fish #lamprey #fossilfish #pennsylvanian #carboniferous

www.esconi.org/esconi_earth...

Mazon Monday #283: Mazon Creek bromalites evidence a specialized, xiphosurid-rich diet for Pennsylvanian predators #fossils #paleontology #MazonMonday #MazonCreek #horseshoecrabs #pennsylvanian #bromalites #coprolites #regurgitalites

www.esconi.org/esconi_earth...

Mazon Monday #282: Pit 11 Shutdown in 1974 #fossils #paleontology #MazonMonday #MazonCreek #coal #coalmining #braidwood #history

www.esconi.org/esconi_earth...

Mazon Monday #281: 283,821 concretions, how do you measure the Mazon Creek? #fossils #paleontology #MazonMonday #MazonCreek #concretions #pennsylvanian #carboniferous #braidwood #essex

www.esconi.org/esconi_earth...

Mazon Monday #280: Palaeocampa anthrax Redux #fossils #paleontology #MazonMonday #MazonCreek #pennsylvanian #lobopod

www.esconi.org/esconi_earth...