Steinkern of a Fossil Gastropod (Prehistoric Snail)
cf. Leptosolen or Volutoderma sp. • Internal mold (Steinkern); Invertebrate Body Fossil
Geological Period
Cretaceous (Upper Cretaceous, likely Coniacian to Campanian)
Estimated Age
Approximately 75 to 90 million years old
Preservation Type
Internal mold (steinkern) formed by the filling of the original shell with fine sediment that lithified, followed by the dissolution of the calcium carbonate shell.
Condition Assessment
Fair to Good; the internal mold is mostly complete and maintains the spiral form, though surface detail from the original shell is absent and there is significant water-wear from river transport.
Taxonomic Classification
Kingdom: Animalia, Phylum: Mollusca, Class: Gastropoda, Order: Neogastropoda, Family: Volutidae (putative)
Morphological Description
A dextrally coiled, turbinate internal mold displaying three to four visible whorls. The specimen shows a gentle apical angle and rounded whorl profiles with visible sutures between them. The aperture is not fully preserved, but the overall geometry suggests a medium-spired snail body shape typical of Cretaceous marine gastropods.
Rock Matrix
Yellowish-beige fine-grained limestone/calcarenite consistent with the Santonian-Campanian deposits of the Aquitaine Basin.
Formation & Location
Vézère River Valley, Dordogne, France; likely originating from the Upper Cretaceous limestone formations common in the Périgord Noir region.
Size & Dimensions
Approximately 4.5 cm in diameter; typical for small to medium-sized gastropods of this era.
Value & Rarity
Estimated Market Value
$10.00 - $25.00 USD
Auction Estimate
$15.00 - $40.00 USD (as part of a bulk lot of regional fossils)
Rarity Assessment
Common; gastropod steinkerns are frequently found throughout the Cretaceous limestone layers of Southwestern France.
Scientific Significance
Provides evidence of marine paleoenvironments in the Aquitaine Basin during the Late Cretaceous high sea levels. This specimen indicates a shallow, warm marine shelf ecosystem.
Preparation Recommendations
Minimal preparation required. Clean with soft brush and water to remove river sediment. Store in a dry environment. No consolidation necessary due to the robust nature of the limestone matrix.
Notable Features
The specimen is a classic 'steinkern' (stone heart), a perfect example of secondary geological replacement where the soft interior of a shell became the only surviving record after the shell itself dissolved.
Notes
found in vezere river, dordogne