Cycad Leaf Fragment (Palaeozamia or Zamites)
Zamites sp. or Otozamites aff. • Body fossil (Compression/Impression); Plant Macrofossil
Geological Period
Jurassic to Early Cretaceous
Estimated Age
Approx. 145 – 180 million years
Preservation Type
Carbonization/Carbonaceous film with mineral replacement. The plant matter has been converted to a thin carbon film, partly replaced by iron oxides (limonite/hematite) giving it a tan/orange hue.
Condition Assessment
Fair to Good. The specimen is incomplete and fragmentary, though the leaflet structure and some venation details remain discernable.
Taxonomic Classification
Kingdom: Plantae; Phylum: Cycadophyta; Order: Cycadales/Bennettitales; Genus: cf. Zamites
Morphological Description
The specimen displays a fossilized plant frond fragment featuring multiple parallel leaflets (pinnae) attached to a central rachis. The leaflets show a characteristic lanceolate shape with slightly rounded bases and distinctive parallel venation patterns running the length of the pinnules.
Rock Matrix
Fine-grained dark grey shale/claystone with iron oxide staining on the bedding plane.
Formation & Location
Possible Yorkshire Coast (Saltwick Formation, UK) or similar Jurassic-aged deltaic deposits in North America or Central Europe.
Size & Dimensions
Approximately 4-6 cm in width; a fragmentary specimen representing a small portion of a much larger frond.
Value & Rarity
Estimated Market Value
$15 - $35 USD
Auction Estimate
$20 - $50 USD (likely as part of a larger fossil plant lot)
Rarity Assessment
Common. Cycad-like fronds are widely distributed in Jurassic and Cretaceous coal-bearing and deltaic shale stratigraphic layers.
Scientific Significance
Provides evidence of mid-Mesozoic terrestrial flora. Cycads were 'dominant' foliage during the Jurassic, reflecting a warm, humid environment and serving as a primary food source for herbivorous dinosaurs.
Preparation Recommendations
No chemical preparation required. Maintain in a dry, low-humidity environment to prevent shale degradation. Should be stored in a padded specimen box to prevent flaking of the carbon film.
Notable Features
The contrast between the orange-tinted fossilized plant tissue and the dark grey matrix makes the morphology easily visible to the naked eye. The attachment point of the leaflets suggests a Bennettitalean affinity.