Fossilized Burrow (Thalassinoides or Ophiomorpha)
Thalassinoides cf. suevicus • Trace fossil (ichnofossil), invertebrate burrow cast
Geological Period
Jurassic to Cretaceous (Callovian to Cenomanian based on the Vaches Noires cliffs context)
Estimated Age
165 to 95 million years ago
Preservation Type
Natural cast (infilling of an open burrow system by denser sediment, followed by lithification and differential weathering of the surrounding softer matrix)
Condition Assessment
Good condition; a solid, complete segment of a burrow system with minor surface weathering typical of marine coastal erosion
Taxonomic Classification
Ichnogenera: Thalassinoides or Ophiomorpha; Producer: Crustacea (Decapoda, e.g., ghost shrimps or lobsters)
Morphological Description
Elongated, sub-cylindrical sediment-filled burrow cast with a relatively smooth to slightly bumpy surface texture, displaying slight constrictions and a roughly uniform diameter along its preserved length.
Rock Matrix
Marly limestone and glauconitic clay characteristic of the coastal formations of Normandy
Formation & Location
Falaises des Vaches Noires (Black Cows Cliffs), Normandy, France; Callovian-Oxfordian argillaceous and marly formations
Size & Dimensions
Approximately 8 to 10 cm in length and 2 cm in diameter, comparable to typical decapod burrow dimensions from this geological setting
Value & Rarity
Estimated Market Value
10 to 30 USD
Auction Estimate
15 to 40 USD
Rarity Assessment
Common
Scientific Significance
Provides direct behavioral evidence of marine invertebrate activity, bioturbation, and paleo-oxygenation levels in shallow shelf environments of the Mesozoic sea covering northern France
Preparation Recommendations
Gentle mechanical cleaning with a soft brush and water to remove adhering clay matrix; no special chemical consolidants required unless the surface is friable
Notable Features
Represents the infilling of a subterranean crustacean dwelling or feeding structure, showcasing the hidden ichnological record preserved in the famous Vaches Noires fossil beds
Notes
falaises des Vaches Noires