Rare Mazon Creek Split Fossil Fern Nodule Macroneuropteris Carboniferous Illinois USA with Certificate of Authenticity

Description

Genuine Mazon Creek Fossil Fern – Macroneuropteris

This is a beautiful and rare Mazon Creek split fossil fern nodule showcasing Macroneuropteris, one of the most iconic plant fossils of the Carboniferous coal forests. Preserved in exquisite detail within an ironstone concretion, this specimen dates to approximately 307 million years ago. The photos show the actual fossil you will receive, with a 1 cm scale cube for full sizing reference. As with all of our offerings, this fossil comes with a Certificate of Authenticity, confirming it is a 100% genuine specimen.

Geological Context

• Geological Period: Carboniferous (Pennsylvanian Subperiod)
• Age: ~307 million years
• Formation: Francis Creek Shale, Carbondale Formation
• Location: Mazon Creek, Illinois, USA

The Mazon Creek fossil beds are world-renowned for their preservation of plants and animals in siderite nodules. Rapid burial in deltaic muds created anoxic conditions that prevented decay and encouraged the growth of mineral nodules around organic remains. This process preserved even delicate structures like fern leaves, producing fossils of extraordinary detail and beauty.

Scientific Classification

• Kingdom: Plantae
• Clade: Pteridophyta (ferns and fern allies)
• Order: Medullosales (seed ferns, often grouped with pteridosperms)
• Genus: Macroneuropteris

Macroneuropteris belongs to the group of seed ferns (pteridosperms), which were dominant in the swampy forests of the Carboniferous. These plants bore large, broad fronds that resemble modern ferns, but they reproduced using seeds rather than spores.

Morphological Features

This specimen preserves a distinctive fern frond leaflet (pinna) of Macroneuropteris.

• Leaf Shape: Large, elongate, and lanceolate, often with a central midrib clearly visible.
• Venation: Fine lateral veins branching off from the central rib, creating a delicate network pattern.
• Texture: The fossil shows excellent definition of leaf margins and venation, a hallmark of Mazon Creek preservation.

The large size of Macroneuropteris leaves allowed these plants to capture sunlight effectively in dense Carboniferous forests. Their structure also made them an important contributor to the vast biomass that later formed coal seams.

Paleoenvironment and Significance

During the Carboniferous, the region of modern-day Illinois was situated near the equator, covered by humid tropical forests and vast coal swamps. The flora was dominated by giant lycopsids, horsetails, seed ferns, and tree ferns. Macroneuropteris was particularly abundant and is considered one of the classic index fossils of Mazon Creek.

Fossils like this specimen provide vital insights into plant evolution, as seed ferns were a transitional group between spore-bearing ferns and seed-bearing plants. Their presence in Mazon Creek nodules also illustrates the diversity and ecological complexity of Carboniferous ecosystems.

Key Details

• Fossil Type: Split siderite nodule containing Macroneuropteris frond
• Age: Carboniferous (~307 million years)
• Formation: Francis Creek Shale
• Locality: Mazon Creek, Illinois, USA
• Authenticity: 100% genuine fossil with Certificate of Authenticity
• Size: See photos with 1 cm scale cube

Collectability and Display

This Macroneuropteris fossil is a superb collector’s piece, representing one of the most classic and recognisable plant fossils in paleontology. Its large, well-preserved frond detail makes it ideal for both educational and display purposes.

Mazon Creek fossils are internationally renowned for their scientific importance and natural beauty. This specimen is not only a striking natural artwork but also a direct link to the lush forests that laid down much of the world’s coal reserves. Adding this piece to your collection offers the opportunity to own a genuine fragment of Earth’s ancient history, beautifully preserved for over 300 million years.