Fossilized Sea Urchin (Echinoid Steinkern / Flint Internal Mold)
cf. Echinocorys scutata or cf. Micraster sp. • Internal Mold (Steinkern) / Body Fossil, Invertebrate Marine Echinoderm
Geological Period
Upper Cretaceous (Santonian to Maastrichtian)
Estimated Age
85 to 66 million years old
Preservation Type
Silicification / Flint replacement as an internal mold (steinkern). The original calcium carbonate shell dissolved away, leaving a silica-rich/flint internal cast formed within sediment.
Condition Assessment
Fair. Specimen shows heavy beach/river tumbling and erosion, causing smoothing of primary diagnostic features like pore pairs and tubercle bases, but preserving overall 3D shape and main ambulacral grooves.
Taxonomic Classification
Phylum: Echinodermata, Class: Echinoidea, Order: Spatangoida (Heart Urchins) or Echinocorythidae
Morphological Description
Sub-globular to heart-shaped calcified/silicified mold showing distinct ambulacral and interambulacral radial grooves running vertically across the dome. Surface demonstrates typical echinoid five-fold pentameral symmetry marked by serial pore pair depressions where the tube feet originally projected. Heavily eroded and rolled cobble habitus.
Rock Matrix
Flint / Chert nodule derived from Cretaceous Chalk beds, with minor chalky white patination and weathering.
Formation & Location
Chalk Group (e.g., White Chalk Subgroup) of Northern Europe, commonly found along coastal beaches and gravel beds in Southern England (e.g., Kent, Sussex, Isle of Wight), France, Denmark, and the Baltic region.
Size & Dimensions
Approximately 4.0 to 5.0 cm in diameter, matching the typical adult size range for Cretaceous regular and irregular echinoids.
Value & Rarity
Estimated Market Value
$10 - $25 USD
Auction Estimate
$15 - $30 USD
Rarity Assessment
Common. Echinoid flint molds are among the most frequently discovered marine fossils in Upper Cretaceous chalk formations and gravel deposits across Northwestern Europe.
Scientific Significance
Illustrates classical silica replacement preservation in deep-marine pelagic chalk environments during the high sea-level stands of the Late Cretaceous. Useful for regional biostratigraphy and paleoecological reconstruction of Cretaceous seafloors.
Preparation Recommendations
No invasive mechanical or chemical preparation required due to extensive erosion. Scrub gently with water and a soft brush to remove loose surface dirt. Store in dry, low-humidity conditions away from abrasives.
Notable Features
Rounded flint steinkern featuring prominent vertical ambulacral grooves displaying characteristic echinoderm pentameral symmetry, preserved as a beach pebble.