Crushing Shark Tooth (or Ray Tooth Battery Fragment)
aff. Ptychodus sp. or cf. Myliobatis sp. • Body fossil; Vertebrate (Chondrichthyes)
Geological Period
Cretaceous to Neogene (likely Miocene or Eocene)
Estimated Age
5 to 100 million years
Preservation Type
Phosphate mineralization (Permineralization); typical dark gray/black coloration indicative of anoxic marine deposition.
Condition Assessment
Fair; heavily water-worn (rolled) with significant loss of fine enameloid detail and fractured edges.
Taxonomic Classification
Phylum: Chordata, Class: Chondrichthyes, Order: Lamniformes or Rajiformes
Morphological Description
Small, dark, elongated specimen with a distinct crushing surface showing faint ridges and a porous underside typical of chondrichthyan osteodentine. The crown appears worn and rounded, suggesting aqueous transport.
Rock Matrix
None attached; specimen appears to be a beach-found or river-worn phosphate nodule/fossil. Likely originated from a glauconitic sandy matrix.
Formation & Location
Commonly found in the Atlantic Coastal Plain (e.g., Calvert Formation, MD) or phosphate mines of Florida/South Carolina.
Size & Dimensions
Approximately 1.5 to 2.5 cm in length; consistent with average pavement teeth from crushing sharks or rays.
Value & Rarity
Estimated Market Value
$5 - $15 USD
Auction Estimate
$10 - $30 USD (only as part of a bulk lot)
Rarity Assessment
Common; these isolated teeth or dental battery fragments are frequently found in lag deposits.
Scientific Significance
Provides data on ancient marine durophagous (shell-crushing) predators and paleo-bathymetry of coastal shelf environments.
Preparation Recommendations
No further preparation needed; rinse with distilled water to remove salt if beach-found and store in a dry, padded container.
Notable Features
Heavy mineralization and 'rolled' texture indicating a long period of erosion and re-deposition in a high-energy environment.