Skirroceras macrum Ammonite Fossil Bajocian France Genuine Jurassic Specimen COA Cephalopod Collectable

Description

Genuine Skirroceras macrum Ammonite Fossil

This is a genuine Skirroceras macrum ammonite fossil from France, dating to the Middle Jurassic, Bajocian Stage. This carefully chosen fossil specimen is an attractive and scientifically interesting piece for collectors of French ammonites, Jurassic fossils, extinct marine cephalopods, natural history specimens, and well-labelled palaeontological display pieces.

The photograph shows the actual fossil you will receive, allowing you to view the individual preservation, shell form, surface detail, colour, matrix, and natural character of this specific specimen before purchase. Full sizing details can be seen in the photo. This fossil includes a Certificate of Authenticity lifetime guarantee generic card, confirming it as a genuine specimen.

Fossil Type, Species and Scientific Classification

Skirroceras macrum is an ammonite, an extinct marine cephalopod belonging to the order Ammonitida. Ammonites were related to modern squid, cuttlefish, octopus, and nautilus, and are among the most recognisable fossils of the Jurassic Period. Their coiled shells, chambered internal structure, varied ornamentation, and rapid evolutionary changes make them highly valued by fossil collectors and important in palaeontology.

This specimen belongs to the genus Skirroceras and the species Skirroceras macrum. Skirroceras is associated with Middle Jurassic ammonite faunas and is generally placed among stephanoceratid ammonites, a group often recognised for robust coiling, rounded whorls, prominent ribbing, and strong sculptural shell form. These ammonites are of particular interest in Bajocian biostratigraphy, where shell features and species occurrences help geologists compare and date marine sedimentary rock layers.

Geological Age and Bajocian Context

This fossil dates from the Bajocian Stage of the Middle Jurassic, approximately 170 to 168 million years ago. The Bajocian was a time of widespread shallow marine environments across much of western Europe, with ammonites forming a diverse and abundant part of ancient sea life.

During this interval, ammonites such as Skirroceras macrum lived as active swimming marine animals. Their chambered shells helped regulate buoyancy in the water column, while the living animal occupied the outer body chamber. After death, the shell could settle onto the sea floor, become buried by sediment, and eventually fossilise through mineralisation, compaction, and long-term geological alteration.

French Jurassic Locality and Depositional Environment

France is well known for fossil-bearing Jurassic sedimentary rocks, including marine deposits that have produced many classic ammonites, belemnites, bivalves, brachiopods, echinoids, gastropods, and other invertebrate fossils. French Jurassic ammonites are popular with collectors because they represent well-studied European faunas and attractive fossil material from ancient marine environments.

The sediments that preserve Bajocian ammonites were generally deposited in shallow marine settings, often involving limestone, marl, clay-rich beds, or carbonate-rich sea-floor deposits. These environments helped preserve shells after burial, allowing mineralisation and geological processes to retain the ammonite’s distinctive coiled form. Depending on the individual specimen, fossils from these settings may show shell ornamentation, ribbing, matrix, mineral staining, natural surface texture, or partial compression.

Ammonite Morphology and Natural Features

Skirroceras macrum displays the classic planispiral ammonite form, with the shell coiled in a flat spiral. The whorls represent successive stages of growth, expanding outward as the ammonite matured. Species within this type of ammonite group are often appreciated for their strong ribbing, rounded whorl shape, and bold fossil appearance.

Depending on preservation, this fossil may show rib detail, whorl curvature, a visible umbilicus, shell ornamentation, mineral colour variation, sedimentary matrix, surface wear, or fossilisation texture. The outer shell shape, ribbing pattern, whorl proportions, and coiling style are key features used in ammonite comparison and identification.

Natural features such as small fractures, worn areas, sedimentary contact marks, matrix attachment, weathered surfaces, mineral deposits, and colour differences are part of the fossil’s geological history. These characteristics add individuality to the specimen and help distinguish a genuine natural fossil from a modern replica or cast.

Collecting, Display and Educational Interest

This Skirroceras macrum ammonite fossil is well suited for display in a fossil cabinet, study, classroom, office, collection drawer, natural history arrangement, or Jurassic fossil collection. Its named species identification, Middle Jurassic Bajocian age, French origin, and classic ammonite form give it strong collecting appeal.

It is suitable for collectors interested in French fossils, Jurassic ammonites, extinct cephalopods, marine invertebrates, palaeontology, geology, and educational fossil specimens. The natural coiled shell form gives the fossil immediate visual impact, while the species name and geological age provide valuable context for anyone interested in prehistoric marine life and the ancient seas of Jurassic Europe.

Authenticity and Specimen Details

This is a genuine Skirroceras macrum ammonite fossil from France, dating to the Middle Jurassic, Bajocian Stage. It includes a Certificate of Authenticity lifetime guarantee generic card. The photo shows the actual fossil you will receive, and full sizing information can be seen in the photo.