Description
Genuine Abbasites abbas Ammonite Fossil
This carefully chosen specimen is a genuine Abbasites abbas ammonite fossil from Calvados in Normandy, France. It dates from the Lower Bajocian interval of the Middle Jurassic and represents an extinct marine cephalopod that inhabited the ancient seas of western Europe approximately 170 million years ago.
Its named species, clearly recorded geological interval and classic French locality give this fossil excellent scientific, educational and collectable interest. It is especially suitable for collectors of ammonites, Middle Jurassic fossils, French palaeontology specimens and natural-history objects with documented provenance.
The photograph shows the exact fossil specimen you will receive. Full sizing and scale information can be seen in the accompanying photograph.
Lower Bajocian Middle Jurassic Geology
The Bajocian is one of the four stages of the Middle Jurassic Period and was named after Bayeux in Normandy. This historical connection makes ammonites from Calvados particularly relevant to the study of Jurassic geology and the development of modern stratigraphy.
During the Lower Bajocian, the area now forming Normandy lay beneath warm marine waters connected to the extensive Jurassic seas of western Europe. Calcium-carbonate mud, fine mineral particles, fragmented shells and the remains of marine organisms accumulated across the seabed.
Through prolonged burial, compaction and natural cementation, these sediments gradually became limestone, marl and other fossil-bearing sedimentary rocks. The surrounding marine ecosystem included ammonites, belemnites, nautiloids, bivalves, brachiopods, gastropods, echinoids and many other invertebrates.
After the ammonite died, its shell settled onto the seabed and was covered by sediment. The original shell material could subsequently be mineralised, replaced or dissolved, leaving a natural impression or a stone-filled internal mould. Its surviving colour, texture, matrix and surface details are products of this long fossilisation process.
Abbasites abbas Shell Characteristics
Abbasites is an uncommon genus of early Middle Jurassic ammonites. Abbasites abbas is the type species of the genus, which was established by the British palaeontologist Sydney Savory Buckman in 1921.
The shell is characteristically compact and planispirally coiled, with successive whorls developing in a single plane around the central umbilical region. Abbasites is generally described as having a small, relatively robust or subglobular shell form rather than the strongly compressed profile seen in some other ammonite groups.
Its ornamentation includes radial ribs that extend across the flanks and may divide relatively high on the sides of the shell. The ribs can weaken or become interrupted around the outer margin, producing a distinctive ventral pattern. Whorl shape, rib density, rib division, umbilical proportions and ventral structure are among the features used by palaeontologists when comparing Abbasites with related ammonites.
Depending on its individual preservation, this specimen may display portions of the coiled whorls, ribbed flanks, central umbilicus, outer margin, internal chambering or surrounding Jurassic matrix. Differences in completeness, mineral staining, matrix coverage and surface texture are natural features of a fossil that has passed through millions of years of burial and geological alteration.
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 animal occupied the final and largest section of the shell, known as the body chamber. The earlier chambers formed the phragmocone, which functioned as part of the ammonite’s buoyancy system. A narrow connecting structure called the siphuncle passed through the chambers and helped regulate the balance of liquid and gas inside them.
As the ammonite grew, it added progressively larger chambers around the outside of its shell. The internal walls separating these chambers are called septa. Where the septa met the shell wall, they produced intricate patterns known as suture lines.
Shell proportions, coiling style, ribbing, ventral features and suture patterns provide important evidence for ammonite identification and classification. Because ammonites evolved rapidly and became widely distributed through ancient seas, their fossils are valuable for comparing and dating Jurassic rock sequences.
Calvados Ammonite from Normandy, France
Calvados is internationally important in the history of Jurassic palaeontology. Its fossil-bearing marine rocks have been studied for generations, and the Bajocian Stage itself takes its name from the Latin form of Bayeux.
Ammonites from Normandy provide evidence of changing sea levels, sedimentary environments and marine biodiversity during the Middle Jurassic. They also allow palaeontologists to trace the development and distribution of different ammonite lineages through relatively narrow intervals of geological time.
A specimen retaining its species identification, geological age and collection locality has greater scientific and collectable significance than an ammonite without recorded provenance. This Abbasites abbas would make a distinctive addition to a specialist ammonite collection, French fossil display, educational cabinet or collection of unusual Middle Jurassic cephalopods.
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 appearance, geological character and collectable appeal.
The photograph shows the actual Abbasites abbas 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 Lower Bajocian ammonite fossil from the Middle Jurassic of Normandy, France.
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