THE FIELD MUSEUM AND THE EARTH SCIENCE CLUB OF NORTHERN ILLINOIS, THE PEOPLE BEHIND MANY MAZON CREEK FOSSIL DISCOVERIES

The Field Museum has one of the most significant collections in the world of fossils from the Mazon Creek Lagerstätte. The coal strip mine spoil heaps, where the majority of these fossils have been collected, is just 50 miles southwest of the museum’s downtown Chicago location. The Mazon Creek fossils occur in siderite concretions in the Pennsylvanian Francis Creek Shale Member of the Carbondale Formation. From the 1950’s to the early 1980’s many amateur fossil collectors scoured the maze of spoil piles searching for these concretions. Many of the collectors gathered together and shared their fossil finds and knowledge of the area with each other and formed a fossil club, the Earth Science Club of Northern Illinois (ESCONI). As new and unknown fossils were discovered they brought their finds to the Field Museum. Curator Eugene S. Richardson Jr. welcomed the amateur fossil collectors and soon a partnership developed. The members of ESCONI shared and donated their fossil find to Richardson and the Field Museum and Richardson helped identify the fossils and gave talks to the club members. Richardson and Field Museum staff often conducted field work with ESCONI members. Knowledge of the fossils and the locality was also shared back to Richardson. Members made maps of locations in the spoil heaps where Tully monsters, jellyfish, worms, and other fossils were particularly abundant. They noted differences in the color and stratification of the concretions from different locations. Most importantly they worked with museum paleontologists discovering specimens and donating many important fossils to the museum. At the first NAPC Meeting in Chicago over 40 ESCONI members displayed their Mazon Creek fossils at a special tour of the Field Museum. Over 70 Mazon Creek fossils are named after ESCONI members and two are named after the organization, a polychaete worm, Esconites zelus, and a larval fish, Esconichthys apyrispo. The Field Museum’s 60,000 specimen collection of Mazon creek fossils would not have been possible without the hard work and generosity of ESCONI.