Fossilized Bone Chunk / Ironstone Concretion
Indeterminate vertebrate bone cf. fossilized bone fragment • Body fossil (indeterminate vertebrate bone fragment) or mineral concretion
Geological Period
Likely Cretaceous or Neogene based on typical surface finds
Estimated Age
5 to 100 million years
Preservation Type
Permineralization or heavy mineral replacement (likely iron-rich minerals such as hematite or goethite)
Condition Assessment
Fair; heavily eroded and water-worn, lacking original anatomical structure or articulation surfaces
Taxonomic Classification
Phylum: Chordata, Class: Indeterminate (possibly Reptilia or Mammalia), Order/Family/Genus: Indeterminate
Morphological Description
Elongated, water-worn nodule with a dark brown ferruginous patina. Visible surface texture shows some fine pitting and linear striations consistent with cortical bone mineral replacement, though lacks distinct diagnostic articulation points.
Rock Matrix
Iron-rich sandstone or clay-ironstone matrix adhering to or replacing the internal structure
Formation & Location
Commonly found in fluvial or coastal deposits, such as the Hell Creek Formation (USA) or the Peace River (Florida)
Size & Dimensions
Approximately 4-6 cm in length and 1.5-2 cm in width, which is small for megafauna but typical for fragmentary river-worn specimens
Value & Rarity
Estimated Market Value
$5 - $15 USD
Auction Estimate
$10 - $20 USD (as part of a bulk lot)
Rarity Assessment
Common; fragmentary, water-worn bone pieces are frequent occurrences in fossiliferous gravel beds
Scientific Significance
Low; provides evidence of vertebrate presence in a specific facies but lacks the diagnostic features required for significant evolutionary or taxonomic research
Preparation Recommendations
No further mechanical preparation suggested. Clean with water and soft brush; store in a dry environment to prevent further oxidation of the iron compounds
Notable Features
Highly polished by natural water action, creating a 'river pebble' appearance while retaining the dense density characteristic of fossilized bone mineral