Belemite Rostrum Fragment
Belemnitida indet. (Specific genus identification requires the apical end/alveolus details) • Body fossil (rostrum) / Invertebrate Cephalopod
Geological Period
Jurassic to Cretaceous
Estimated Age
Approx. 66 to 201 million years
Preservation Type
Recrystallized calcite replacement; sturdy biocrystalline structure
Condition Assessment
Fair; partial specimen (fragment) showing significant weathering and missing the phragmocone/alveolar region
Taxonomic Classification
Phylum: Mollusca, Class: Cephalopoda, Order: Belemnitida, Family: Belemnitidae
Morphological Description
Conical, bullet-shaped calcitic internal shell known as a rostrum. Features a tapering cylindrical form with a textured surface showing longitudinal striations or growth layers in cross-section.
Rock Matrix
Specimen is a loose find; likely derived from limestone or marl matrix
Formation & Location
Common in global formations like the Oxford Clay (UK) or Pierre Shale (USA); widely found in Mesozoic marine deposits
Size & Dimensions
Approximately 3-4 cm in length; typical for a partial distal fragment of a medium-sized belemnite
Value & Rarity
Estimated Market Value
$2 - $10 USD
Auction Estimate
$5 - $15 USD (usually sold in bulk lots for study)
Rarity Assessment
Common; belemnite rostra are abundant in marine fossil beds worldwide
Scientific Significance
Belemnites are important index fossils for dating Mesozoic strata and provide data on ancient ocean temperatures via oxygen isotope analysis of the calcite.
Preparation Recommendations
Requires minimal prep; clean with water and soft brush. Store in a dry environment to prevent calcite degradation.
Notable Features
Shows the distinct internal solid calcitic structure designed for counterbalance in the prehistoric squid-like cephalopod.