Above is an image of a horsetail trunk plant fossil called Calamites sp. This plant fossil dates to the Carboniferous (Pennsylvanian) Period (354-290 mya). It was found Mazon Creek, Illinois, USA. The layer fossils are found is in Francis Creek Shale.
The fossil was on display in the Evolving Planet section of The Field Museum of Natural History in Chicago Illinois, USA as of August 2020. Accession number is UP2561. They have quite an extensive collection of Mazon Creek fossils at the exhibit.
The Field Museum produced a visual PDF of some of the fossils found at Mazon Creek. It can be found at this link:
Mazon Creek Collections Database at Illinois State Museum
http://www.museum.state.il.us/databases/geology/mazoncreek/graphical/index.php
