Felted Plant Matter / Woody Carbonaceous Compression
Incertae sedis; cf. Cordaites (leaf fragments) or aff. Calamites (stem bark) • Body fossil (carbonaceous compression/impression), Plant Macrofossil
Geological Period
Carboniferous (Pennsylvanian sub-period)
Estimated Age
299 to 318 million years
Preservation Type
Carbonization and distillation; organic material has been reduced to a thin carbon film on the bedding plane of the rock.
Condition Assessment
Fair to Poor; the specimen is fragmentary, lacks distinct diagnostic apical or basal features, and shows significant weathering and matrix obscuration.
Taxonomic Classification
Kingdom: Plantae, Phylum: Tracheophyta (Vascular plants), Order: Pteridospermales (Seed ferns) or Lepidodendrales (Lycopsids)
Morphological Description
The specimen exhibits dark, flattened carbonaceous streaks and fibrous longitudinal textures. There are visible striations suggesting vascular tissue or ribs of a stem, along with patches of iron oxide (limonite) staining common in coal-bearing shales.
Rock Matrix
Grey micaceous siltstone or carbonaceous shale; shows fine laminations and typical clastic texture associated with deltaic deposits.
Formation & Location
Likely sourced from the Pottsville Formation (Appalachian Basin, USA) or the Coal Measures of the UK/Europe (e.g., Mazon Creek equivalent lithology).
Size & Dimensions
Approximately 5-6 cm in maximum diameter; the visible fossilized fragments are fragmentary, ranging from 1-3 cm in length.
Value & Rarity
Estimated Market Value
$5.00 - $15.00 USD
Auction Estimate
$10.00 - $25.00 USD (as part of a multi-specimen bulk lot)
Rarity Assessment
Common; fragmentary plant material in Carboniferous shale is globally abundant in coal-mining regions.
Scientific Significance
Provides evidence of late Paleozoic terrestrial biomass and paleoenvironmental conditions, specifically the buildup of peat and organic matter in swampy, low-oxygen environments.
Preparation Recommendations
Dry mechanical cleaning with a soft brush. Seal with a light application of Paraloid B-72 if the shale exhibits signs of flaking or 'pyrite rot' (though none is currently visible).
Notable Features
Features distinct orange-brown limonitic staining which highlights the organic impressions against the dark grey matrix; preservation shows the high compression ratio of the original vegetable matter.