Sphaeroceras brongniarti Ammonite Fossil UK Bajocian with COA

Description

Genuine Sphaeroceras Ammonite Fossil

This genuine ammonite fossil is identified as Sphaeroceras brongniarti and comes from the Inferior Oolite Group in the UK. It dates to the Bajocian Stage of the Middle Jurassic and is a carefully selected British specimen with useful species, geological-group, and age information. The photographs show the exact fossil offered for sale, so the ammonite pictured is the specimen you will receive.

Sphaeroceras brongniarti was an extinct marine cephalopod with a compact, chambered, coiled shell. As the animal grew, it constructed progressively larger chambers around the outer whorl. The living ammonite occupied the final body chamber, while the older sealed chambers contributed to buoyancy control. Ammonites were relatives of living squid, cuttlefish, and nautiluses, although they belonged to their own extinct branch of cephalopods.

Bajocian Geological Age

The Bajocian is a stage within the Middle Jurassic Period. During this interval, shallow marine environments covered parts of what is now Britain and supported diverse ammonite communities. Shells could settle on the sea floor and become buried within sediment. Compaction, mineralisation, and geological change then preserved some of them as fossils.

Ammonites evolved rapidly and were widely distributed through Jurassic seas. Their changing shell forms make them especially valuable to geologists for comparing sedimentary rocks and establishing relative ages. The documented Bajocian age gives this specimen a clear position within the Jurassic succession and makes it suitable for a collection organised by geological stage.

Inferior Oolite Group

The Inferior Oolite Group is an important Middle Jurassic rock succession in southern Britain. It includes marine limestones and associated beds that preserve ammonites, bivalves, brachiopods, and other evidence of ancient sea-floor communities. The term oolite refers to limestone that commonly contains small rounded carbonate grains formed in moving shallow water, although the group contains a variety of sedimentary rocks.

Burial within these deposits protected part of the ammonite shell. Natural matrix, mineral colour, surface texture, small breaks, and differences in preservation all reflect the specimen’s geological history. These characteristics are genuine features of an ancient fossil rather than signs of modern manufacture.

Shell Form and Collectable Detail

Sphaeroceras ammonites are notable for their rounded, strongly inflated shell form. Their compact coiling gives them a distinctive appearance compared with flatter or more openly coiled ammonites. Examine the photographs for the visible whorls, ribbing, shell outline, and preserved surface features on this individual piece.

Whorl proportions, rib pattern, and changes in ornamentation are among the morphological details used when comparing ammonites. Every fossil preserves a different combination of shell and surrounding rock, making each specimen unique. The photographs provide useful views of the actual piece and show its condition, proportions, and natural character more clearly than a generic description.

British Jurassic Fossil

A specimen with a named species, geological group, and stage provides meaningful context for a British fossil collection. This example can complement displays arranged by ammonite genus, Middle Jurassic age, Inferior Oolite geology, or UK provenance. It also offers an engaging starting point for discussing ammonite growth, fossil preservation, biostratigraphy, and ancient marine ecosystems.

Exact Specimen, Size and Authenticity

Full sizing is shown in the photographs, which provide the clearest scale information for this individual fossil. The images are not stock photographs and do not represent a similar example. They show the exact Sphaeroceras brongniarti ammonite that will be supplied.

This is a genuine fossil specimen and includes a generic Certificate of Authenticity card with a lifetime guarantee. It has been carefully chosen for its distinctive shell form, Bajocian age, Inferior Oolite provenance, and British origin. It makes a memorable addition to a cabinet collection, educational display, office, study, or gift for anyone interested in authentic Jurassic fossils.