FREE: Fern Fossil Leaf from Mason Creek Illinois

The listing, Fern Fossil Leaf from Mason Creek Illinois has ended.

Where do they come from? Well on the dumps of coal strip mines of northestern Illinois - some of them not far from downtown Chicago - collectors find curious rounded nodules of rock. These nodules are concretions of siderite, or iron carbonate, and naturally split along the middle. With a careful tap from a rock hammer, a split nodule may reveal a beautifully preserved seed-fern leaf, a shrimp or millipede, or even a Tully monster. This is the Carboniferous-age Mazon Creek locality (or more accurately a set of localities called the Francis Creek Shale, of which Mazon Creek itself is one) whose uniquely preserved fossils provide a glimpse of the history of many organisms that would otherwise have left little trace.

This one measures approximately 3" long by just under 2" wide. It clearly shows the leaf impression on this concretion rock