Description
Authentic Mazon Creek Fossil Fern – Annularia Whirls
This is a rare Mazon Creek split fossil fern nodule preserving multiple whorls of Annularia, a distinctive foliage type of the extinct tree-like horsetail Calamites. Found in the world-renowned Mazon Creek fossil beds of Illinois, USA, this specimen dates back to the Carboniferous Period (~307 million years ago). The piece has been carefully selected for its clear preservation of radiating leaf structures, and the photographs show the actual specimen you will receive. Every fossil comes complete with a Certificate of Authenticity, assuring collectors and enthusiasts of its genuine origin.
Geological Context
- Geological Period: Carboniferous (Pennsylvanian Subperiod)
- Age: Approximately 307 million years old
- Formation: Francis Creek Shale, Carbondale Formation
- Provenance: Mazon Creek, Illinois, USA
The Mazon Creek locality is one of the most famous fossil Lagerstätten in the world. Fossils here are preserved in siderite nodules, formed when rapid burial in deltaic muds led to mineralisation that protected fine details of plant and animal remains. These conditions produced exceptional fossils, including soft tissues, delicate plant structures, and detailed impressions not normally preserved.
Scientific Classification
- Kingdom: Plantae
- Division: Sphenophyta (horsetail relatives)
- Order: Equisetales
- Genus: Annularia
Annularia leaves belonged to the towering horsetail-like plants known as Calamites, which could grow up to 20 meters tall. These plants thrived along river margins and swampy lowlands of the Carboniferous coal forests, contributing greatly to the lush vegetation that formed much of today’s coal deposits.
Morphological Features
This specimen highlights the striking whorled arrangement of leaves, a hallmark of Annularia.
- Whorled Patterns: Multiple radiating leaf sets (“whirls”) preserved across the nodule.
- Leaf Shape: Narrow, linear leaves arranged symmetrically in starburst formations.
- Preservation: Excellent detail showing the natural radiating structure typical of the species.
The whorls represent successive leaf nodes along the stem of Calamites, which produced distinctive foliage in repeating circular patterns. These features made the plant highly efficient in capturing sunlight in dense swamp forest environments.
Paleoenvironment and Significance
During the Carboniferous, Illinois was located near the equator and covered by vast tropical forests. These swampy environments, dominated by giant lycopsids, seed ferns, horsetails, and tree ferns, provided the conditions that would later form extensive coal deposits.
The Mazon Creek nodules capture this ancient environment in exquisite detail, offering insights into plant diversity and evolution during one of Earth’s most important geological intervals. Fossils like Annularia are key for paleobotanists, as they help reconstruct the structure and ecology of Carboniferous forests.
Key Details
- Fossil Type: Split siderite nodule containing Annularia foliage whirls
- Age: Carboniferous (~307 million years old)
- Formation: Francis Creek Shale, Carbondale Formation
- Location: Mazon Creek, Illinois, USA
- Authenticity: 100% genuine fossil with Certificate of Authenticity
- Size: Refer to photos with 1cm scale cube for exact dimensions
Collectability and Display
This Annularia specimen is both scientifically significant and visually striking. The multiple whorls preserved on the nodule create a captivating natural starburst design that makes it an impressive display piece.
Mazon Creek fossils are highly sought after by collectors worldwide due to their exceptional preservation and historical importance. This fossil would make an outstanding addition to any collection of Carboniferous plants, paleobotany specimens, or natural history treasures. Owning a piece of the Mazon Creek flora is an opportunity to hold a genuine relic of Earth’s ancient swamp forests, preserved for over 300 million years.
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