Ammonite fragment (likely Kosmoceras or similar heteromorph/uncoiled or distorted ammonite whorl)
Kosmoceras cf. or indeterminate ammonite fragment • Body fossil, invertebrate marine mollusk
Geological Period
Jurassic (Callovian to Oxfordian epochs) to Cretaceous
Estimated Age
163 to 157 million years old
Preservation Type
Calcitic replacement and internal/external mold preservation within a marly-limestone matrix
Condition Assessment
Fair; highly fragmented, incomplete single whorl section with weathered surface details
Taxonomic Classification
Phylum Mollusca, Class Cephalopoda, Subclass Ammonoidea, Order Ammonitida, Family Kosmoceratidae
Morphological Description
Small, fragmented ammonite portion displaying prominent ribs or tubercles along the whorl section. The surface shows rugose ornamentation typical of middle-to-late Jurassic ammonites found in the Vaches Noires cliffs.
Rock Matrix
Glauconitic and argillaceous limestone, typical of the coastal cliff formations in Normandy
Formation & Location
Falaises des Vaches Noires, Calvados department, Normandy, France; Oxfordian/Callovian formations
Size & Dimensions
Approximately 1.5 cm to 2 cm in length, comparing to a 2 Euro coin (25.75 mm diameter)
Value & Rarity
Estimated Market Value
5 to 15 USD
Auction Estimate
10 to 20 USD
Rarity Assessment
Common; frequently found as fragments along the eroding Vaches Noires cliffs
Scientific Significance
Illustrates the rich marine biodiversity of the Jurassic shallow seas that once covered northern France, useful for local biostratigraphy
Preparation Recommendations
Gentle mechanical cleaning with a soft brush and water to remove excess clay matrix; store in a dry environment
Notable Features
Distinctive ribbing pattern visible on the curved fragment, recovered directly from a famous European fossil-collecting locality
Notes
falaises des Vaches Noires