Fossil Leaf Impression / Gymnosperm Leaf
cf. Dicroidium sp. or Zamites sp. • Plant body fossil - carbonaceous impression / compression in red mudstone
Geological Period
Triassic to Early Jurassic
Estimated Age
190–230 million years
Preservation Type
Impression with minor carbonization; organic material has largely been replaced or oxidized, leaving a darkened imprint.
Condition Assessment
Fair; the impressions are somewhat weathered and lack the high-contrast detail or complete venation seen in museum-grade specimens. The matrix is fractured.
Taxonomic Classification
Kingdom: Plantae; Phylum: Pteridophyta or Gymnospermophyta; Order: Cycadales or Peltaspermales (tentative)
Morphological Description
Faint linear and lanceolate leaf impressions on a fine-grained sedimentary surface. Visible characteristics include elongated, parallel-veined or mid-veined segments (pinnules) typical of seed ferns or cycad-like foliage. The texture is grainy with slight color contrast between the organic residue and the matrix.
Rock Matrix
Ferruginous (iron-rich) siltstone or mudstone, commonly known as 'red beds', exhibiting a fine-grained clastic texture.
Formation & Location
Likely the Chinle Formation (USA), Newark Supergroup (USA), or Karoo Basin (South Africa/Australia/Antarctica), known for terrestrial red-bed flora.
Size & Dimensions
Approximately 5 cm to 8 cm in length; the leaf segments themselves are roughly 1.5 cm to 3 cm, consistent with juvenile or fragmented Triassic foliage.
Value & Rarity
Estimated Market Value
$15.00 - $35.00 USD
Auction Estimate
$20.00 - $45.00 USD
Rarity Assessment
Common; while plant fossils are scientifically valuable, fragmented leaf impressions in red-bed mudstone are widely distributed and frequently found.
Scientific Significance
Provides data on Mesozoic terrestrial flora and paleo-climatology. Red-bed fossils indicate seasonal wetting and drying cycles in ancient floodplains or lacustrine environments.
Preparation Recommendations
No invasive preparation is recommended due to the soft nature of the mudstone. Keep in a low-humidity environment to prevent the iron-rich matrix from further oxidation or crumbling. Use a supportive foam-lined box for storage.
Notable Features
The specimen is localized within a distinct 'red-bed' sediment, which is diagnostic of specific oxidized Permian-Triassic environments. The presence of multiple leaf fragments suggests a high density of local vegetation at the time of deposition.