Description
Genuine Stephanoceras scalare Ammonite Fossil
This carefully chosen specimen is a genuine Stephanoceras scalare ammonite fossil from Calvados in Normandy, France. It dates from the Bajocian Stage of the Middle Jurassic and represents an extinct marine cephalopod that inhabited the warm seas of western Europe approximately 168–171 million years ago.
The combination of a named ammonite species, recognised Middle Jurassic age and recorded Normandy locality gives this specimen excellent geological, educational and collectable interest. It is particularly suitable for collectors of ammonites, French fossils, Jurassic marine life, extinct cephalopods and historically important European geological specimens.
The photograph shows the actual fossil specimen you will receive. Full sizing and scale information can be seen in the accompanying photograph.
Bajocian Middle Jurassic Geology
The Bajocian is one of the four stages of the Middle Jurassic and takes its name from Bayeux in Normandy. This connection makes ammonites from Calvados especially relevant to the history of Jurassic geology and palaeontology.
During the Bajocian, the area now forming northern France was covered by warm, shallow to moderately deep marine waters. These seas formed part of a wider network of marine basins extending across western Europe. Carbonate mud, fine mineral particles, shell fragments and the remains of marine organisms accumulated across the seabed.
Over millions of years, burial, compaction and natural cementation transformed these sediments into fossil-bearing limestone, marl and related sedimentary rocks. The ancient marine ecosystem supported ammonites, nautiloids, belemnites, brachiopods, bivalves, gastropods, echinoids and numerous other invertebrates.
When an ammonite died, its shell could sink to the seabed and become covered by sediment. The original aragonitic shell might later be mineralised, replaced or dissolved, leaving an impression, external mould or stone-filled representation of the chambered interior. The colour, texture, matrix and preserved details visible today are products of this long fossilisation process.
Stephanoceras scalare Shell Morphology
Stephanoceras is an important Middle Jurassic ammonite genus and the type genus of the family Stephanoceratidae. It belongs to the superfamily Stephanoceratoidea within the order Ammonitida.
Members of the genus are recognised for their robust, planispirally coiled shells and strongly developed ornamentation. The shell is generally evolute, meaning that much of the earlier coiling remains visible within a comparatively open central umbilicus.
Primary ribs originate near the umbilical region and extend across the flanks. These ribs commonly strengthen into tubercles or raised nodes before dividing into two or occasionally more secondary ribs. The secondary ribs continue across the rounded outer margin, known as the venter. This combination of pronounced ribbing, branching ornament and tuberculation gives Stephanoceras ammonites their distinctive sculptured appearance.
Shell proportions and ornamentation could change as the animal matured. Inner whorls may display finer, more closely spaced ribs, while later growth can become broader and more strongly ornamented. Depending on its individual preservation, this Stephanoceras scalare specimen may retain portions of the coiled whorls, ribbed flanks, tubercles, umbilical region, ventral margin, internal chambers or surrounding Jurassic matrix.
Each genuine ammonite is naturally unique. Differences in preservation, mineral colouring, completeness, matrix coverage, surface texture and minor fractures record the specimen’s individual biological and geological history.
An Extinct Jurassic Marine Cephalopod
Ammonites were marine molluscs related to living squid, cuttlefish, octopuses and nautiluses. Unlike most modern cephalopods, they possessed a hard external shell divided internally into a succession of chambers.
The living animal occupied the final and largest section, known as the body chamber. The older chambers formed the phragmocone, which functioned as part of the ammonite’s buoyancy system. A narrow organic tube called the siphuncle connected the chambers and allowed the animal to regulate the balance of liquid and gas within them.
As the ammonite grew, it constructed progressively larger chambers around the outer edge of its shell. The internal walls separating the chambers are called septa. Where these septa met the shell wall, they formed intricate patterns known as suture lines.
Shell form, ribbing, tubercle arrangement, whorl proportions, umbilical width and suture patterns are among the features palaeontologists use when identifying and classifying ammonites. Because ammonites evolved rapidly and were widely distributed through ancient seas, their fossils are also valuable for dating and correlating Jurassic rock layers.
Calvados Fossil from Normandy, France
Calvados is internationally associated with the study of Jurassic rocks and fossils. The Bajocian Stage was named after Bayeux, and ammonites from Normandy have played an important role in understanding and subdividing Middle Jurassic marine deposits.
Fossils from this region provide evidence of ancient sea levels, sedimentary environments, ammonite evolution and the diverse marine communities that existed while dinosaurs inhabited nearby landmasses. A specimen retaining its species identification, geological stage and collection locality carries greater scientific and collectable significance than an ammonite without recorded provenance.
This Stephanoceras scalare would make an attractive addition to a specialist ammonite collection, geological study cabinet, educational display or natural-history collection.
Actual Specimen with Certificate of Authenticity
This is a genuine fossil specimen and not a cast, replica or reproduction. It has been individually selected for its natural form, geological character and collectable appeal.
The photograph shows the exact Stephanoceras scalare ammonite fossil you will receive. Full sizing is shown in the photograph.
A generic Certificate of Authenticity card is included with a lifetime guarantee of authenticity, providing lasting confidence that this is a genuine Bajocian ammonite fossil from the Middle Jurassic of Normandy, France.
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