This is Mazon Monday post #343. What’s your favorite Mazon Creek fossil? Tell us at esconi.info@gmail.com.

---

The Mazon Creek Fossil Day for 2026 will be held on October 10th, 2026 at the Coal City Library. See you there!

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.

Founded in the 1960s by the late Eugene Richardson Curator of Fossil Invertebrates at the Field Museum in Chicago Illinois, the Mazon Creek Project was originally an attempt to encourage more communication between paleontologists and amateur collectors. After Peabody Coal Company sold Pit 11 to Commonwealth Edison for the construction of the Braidwood Nuclear Power Plant, some areas were lost to collecting. The main goal of the project became keeping the Mazonia-Braidwood Conservation Area open for collecting by scientists, school children, scout groups, and visitors from other states. Some of the islands in the cooling pond and land to the south were leased to the State of Illinois for fishing and fossil collecting. Fossil collecting is open to all from March 1st to September 30th.

“Mazon Creek Fossils hold a special place in paleontological record. Because conditions of life, of death, and of burial were unusually propitious, we find a more complete record of plant and animal populations than in most other fossil occurrences….I suppose that these elegant fossils have been collected…for centuries… But we have no inkling of any collections made by the Indians. The tradition that continues to the present has begun in the mid-nineteenth century, when there were already established towns and farms in the Illinois valley…” Eugene Richardson, The Mazon Creek Fossil Flora

ESCONI members, including Andy Hay and Jack Wittry, were instrumental in the “Mazon Creek Project” and because of their and other ESCONI members efforts we can collect at Pit 11 even today!  ESCONI Hill was named after the club and at one time was one of the most popular collecting areas.

Here’s what the area looked like in the 1990’s (photos from Ralph Jewell).

Here’s the announcement for the second event from the Mazon Creek Project newsletter, which was held in September 1985.

There was a short write up of this event in the Paleontology Study Group report in the November 1985 ESCONI newsletter.

Several members attended the Mazon Creek Project meeting at Northeastern Illinois University. Bret Beal of Michigan presented a program on the significance of Mazon Creek spiders. Jarmila Peck (insects) will be coming in October-November. Fred Schram plans a December visit. Ida Thompson will be here sometime this year. Clay Bruner of the Field Museum is renaming blades. Charles Marshall is redescribing the lungfish.

Andy Hay found a reference to the freeze-thaw method in one article from England published in 1907. The authors got the idea from an Austrian count. And– we thought this freeze-thaw idea was new!

Interesting artwork distributed for one of the events held at the Burpee Museum.  The art piece was produced by Lonny Stark and is titled “Mazon Creek Chelicerates”.

Here is the Mazon Creek newsletter announcement and itinerary for the 1990 event on October 27th, 1990.

Long time ESCONI member Ralph Jewell took this video at the 1990 event. Thanks, Ralph! Here’s Ralph around 1990 at an Open House.

This video is an interesting look back.