Segmented Echinoid Test Fragment / Cidaris Spine or Test Fragment
Cidaris cf. or related irregular/regular echinoid test fragment • Body fossil, Invertebrate marine fossil (Echinodermata)
Geological Period
Jurassic (Callovian to Oxfordian)
Estimated Age
163 to 157 million years old
Preservation Type
Calcitic replacement / fossilization typical of echinoderm skeletal plates
Condition Assessment
Good condition; shows clear structural features and segmentation, though it represents an incomplete, isolated fragment rather than an entire test.
Taxonomic Classification
Phylum Echinodermata, Class Echinoidea, Order Cidaroida, Family Cidaridae
Morphological Description
Elongated, curved fragment displaying prominent parallel ribbed structures resembling segmented columns or ambulacral/interambulacral plates of an echinoid. The surface exhibits regular transverse ridges separated by deep grooves, giving it a segmented or vertebra-like appearance.
Rock Matrix
Marly limestone / argillaceous matrix derived from coastal cliff formations
Formation & Location
Falaises des Vaches Noires (Black Cows Cliffs), Normandy, France
Size & Dimensions
Approximately 30 mm in length, comparable in scale to a standard 2-euro coin (25.75 mm diameter)
Value & Rarity
Estimated Market Value
15 to 40 USD
Auction Estimate
20 to 50 EUR
Rarity Assessment
Common, frequently found weathering out of the rich fossiliferous clay and limestone layers of the Vaches Noires cliffs.
Scientific Significance
Provides insight into the diverse shallow marine invertebrate fauna of the Jurassic European epicontinental seas, specifically contributing to the paleoecological understanding of benthic echinoid communities.
Preparation Recommendations
Gently clean with a soft brush and water to remove loose matrix. Store in a dry, stable environment away from excessive humidity.
Notable Features
Distinct, highly regular ribbed symmetry which often leads to initial misidentification as a vertebrate fossil (such as a fish vertebra or small reptile bone) by amateur collectors.
Notes
falaises des Vaches Noires