Carboniferous Seed Fern Frond
Alethopteris cf. serli • Plant body fossil; carbonization/impression in shale
Geological Period
Carboniferous (Pennsylvanian subperiod)
Estimated Age
300 to 310 million years
Preservation Type
Carbonized film and impression. The plant matter has been converted to a thin carbon layer, though much has weathered away, leaving a clear impression in the host rock.
Condition Assessment
Fair; the specimen is weathered and the carbon film is partially lost. The venation is visible but lacks the high-contrast detail found in nodules.
Taxonomic Classification
Kingdom: Plantae, Phylum: Pteridospermatophyta, Order: Medullosales, Family: Alethopteridaceae, Genus: Alethopteris
Morphological Description
The specimen shows a partial frond fragment with pinnules. Pinnules are broadly attached at the base (decurrent), slightly confluent, with a prominent central vein and secondary veins arching toward the leaf margins.
Rock Matrix
Iron-stained silty shale or sideritic mudstone. The orange-red coloration is due to the oxidation of iron minerals (limonite/hematite) within the matrix.
Formation & Location
Likely the Pottsville Formation of the Warrior Coal Basin, found frequently in the vicinity of Westover and Jefferson County, Alabama.
Size & Dimensions
Approximately 5 to 7 cm in length; typical for a fragmented macrofossil of this genus in the Alabama coal fields.
Value & Rarity
Estimated Market Value
$10 - $25 USD
Auction Estimate
$15 - $30 USD
Rarity Assessment
Common; Alabama's Pottsville Formation is globally famous for producing mass quantities of these plant fossils in coal mine tailings.
Scientific Significance
Provides evidence of the 'Coal Age' swamp ecosystems of the Appalachian Basin. Seed ferns like Alethopteris were critical components of the tropical lowlands during the Pennsylvanian.
Preparation Recommendations
No invasive preparation needed. Keep dry to prevent further oxidation of the iron-rich matrix. Should be stored in a padded box to prevent crumbling of the shale edges.
Notable Features
The specimen is a classic example of Alabama 'red rock' flora, where iron oxidation has highlighted the fossil impression against a vibrant terrestrial matrix.
Notes
Westover, Alabama