Oyster or Scallop Fragment
cf. Gryphaea sp. or Exogyra sp. fragment • Body fossil, Invertebrate (bivalve mollusk)
Geological Period
Jurassic to Cretaceous (specifically Callovian to Oxfordian based on the Vaches Noires location)
Estimated Age
165 to 155 million years
Preservation Type
Original calcitic shell material preserved with some surface weathering and sediment infill
Condition Assessment
Fair; incomplete fragment, heavily worn edges, but showing distinct surface ornamentation
Taxonomic Classification
Phylum: Mollusca, Class: Bivalvia, Order: Ostreida, Family: Gryphaeidae or Ostreidae, Genus: cf. Gryphaea or Exogyra
Morphological Description
Fragment of a heavily ribbed bivalve shell showing prominent, coarse radial ribs and corrugated growth ridges, characteristic of certain oysters or pectinids.
Rock Matrix
Argillaceous limestone / marly matrix characteristic of the coastal cliffs of Normandy
Formation & Location
Falaises des Vaches Noires, Normandy, France
Size & Dimensions
Approximately 25mm in maximum length, relative to the 2-euro coin (25.75mm diameter)
Value & Rarity
Estimated Market Value
$2 - $10
Auction Estimate
$0 - $5
Rarity Assessment
Common, frequently found weathering out of the clay and limestone cliffs at Vaches Noires
Scientific Significance
Illustrates typical shallow marine shelf fossil assemblages of the Jurassic-Cretaceous transition in the Anglo-Paris Basin
Preparation Recommendations
Gentle mechanical cleaning with a soft brush to remove adhering clay matrix; store in a dry environment
Notable Features
Pronounced coarse plications (ribs) typical of certain cemented bivalves adapted to high-energy shallow marine environments
Notes
falaises des Vaches Noires