Fossil Ammonite Oppelia fallax Bajocian Jurassic Calvados France with Certificate of Authenticity

Description

This listing offers a fine Oppelia fallax ammonite fossil from the Bajocian stage of the Middle Jurassic Period, approximately 170–168 million years old. Discovered in the classic fossil-rich deposits of Calvados, Normandy, France, this specimen represents an excellent example of an ammonite genus highly valued for its scientific significance and elegant shell structure. With its provenance from one of Europe’s most important Jurassic localities, this fossil makes a superb addition for collectors, educators, and enthusiasts alike.

All of our fossils are 100% genuine specimens and are supplied with a Certificate of Authenticity. The photographs show the exact fossil you will receive, with a 1 cm scale cube and rule squares included for precise sizing.

Geological Context and Age

This ammonite originates from the Bajocian stage, part of the Middle Jurassic, dating to around 170–168 million years ago. During this period, much of northern France was covered by shallow epicontinental seas connected to the Tethys Ocean. These warm marine environments provided ideal conditions for ammonites, marine reptiles, bivalves, brachiopods, and early corals to thrive.

The Jurassic formations of Calvados are particularly well known for producing ammonites of excellent preservation, which are widely used in biostratigraphy. Ammonites such as Oppelia fallax are key index fossils, enabling geologists to correlate Bajocian-aged rocks across Europe and beyond. This makes specimens from this locality both scientifically and historically important.

Morphology and Distinctive Features

Oppelia fallax is part of the family Oppeliidae, within the superfamily Haploceratoidea of the order Ammonitida. The genus is characterised by its compressed, discoidal shell, usually smooth or with fine striations, and an involute coiling that conceals earlier whorls. The venter (outer rim) is typically narrow and rounded, while the sutures are moderately complex, distinguishing it from related genera.

This specimen displays the diagnostic flattened discoidal form and smooth flanks of the genus. The elegant symmetry of the shell and its streamlined morphology indicate an active, free-swimming nektonic lifestyle. Ammonites like Oppelia fallax were likely fast swimmers, preying on small crustaceans and fish in the Jurassic seas. Their morphology reflects adaptation to open marine conditions, where hydrodynamic efficiency was key to survival.

Scientific Importance

Ammonites of the genus Oppelia are crucial for refining Jurassic stratigraphy. Oppelia fallax in particular is a biostratigraphically important species, helping define Bajocian biozones. Its relatively rapid evolutionary turnover and widespread geographic distribution make it an essential marker fossil.

In addition to their stratigraphic utility, specimens like this contribute to our understanding of Jurassic marine ecosystems. By studying the morphology, distribution, and associated faunas, palaeontologists gain valuable insight into evolutionary patterns, palaeobiogeography, and environmental conditions of the Middle Jurassic seas.

Collector and Display Value

This Oppelia fallax ammonite fossil from Calvados, France is both scientifically valuable and aesthetically appealing. Its elegant, streamlined form makes it a striking display piece, while its precise provenance adds significant collecting value. Unlike more common Jurassic ammonites, Oppelia fallax is sought after for its importance in stratigraphy and its distinctive morphology.

Whether displayed in a cabinet, used for teaching, or kept as part of a private collection, this specimen represents a tangible link to the Jurassic seas of 170 million years ago. Its rarity and excellent provenance ensure it will be a prized addition to any collection of ammonites or Jurassic fossils.

Your Guarantee of Authenticity

• 100% genuine Oppelia fallax ammonite fossil from Calvados, Normandy, France
• Geological age: Bajocian stage, Middle Jurassic (approx. 170–168 million years old)
• Supplied with a Certificate of Authenticity
• Exact specimen shown in photographs (no stock images used)
• Scale cube and rule squares = 1 cm (see photos for accurate sizing)

This Oppelia fallax ammonite fossil is a scientifically important and visually elegant specimen from the Bajocian deposits of Normandy. Its rarity, provenance, and guaranteed authenticity make it an excellent addition to any fossil collection.