Description
Genuine Sonninia cf. sowerbyi Ammonite Fossil – Bajocian, Somerset
This genuine fossil ammonite is identified as Sonninia cf. sowerbyi, a collectable Middle Jurassic ammonite from the Inferior Oolite Group at Bruton, Cole Syncline, Somerset, UK. Dating to the Bajocian Stage of the Middle Jurassic, this specimen is approximately 170 million years old and represents a classic British ammonite from the warm shallow seas that once covered parts of south-west England.
The “cf.” in the identification means “compares with”, indicating that the fossil shows strong similarities to Sonninia sowerbyi, while allowing for natural variation, preservation, or the limits of species-level identification. This is a careful and appropriate way to label fossil ammonites, especially where shell features may be partly worn, compressed, or affected by preservation.
This fossil is a carefully chosen specimen, with the photograph showing the actual fossil you will receive. Full sizing can be seen in the photo. It is supplied as a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card, making it an excellent addition to a fossil collection, natural history display, educational collection, or British Jurassic ammonite assemblage.
Fossil Type and Species
Ammonites were extinct marine cephalopods related to modern squid, cuttlefish, octopus, and nautilus. They lived inside coiled, chambered shells, with the animal occupying the final body chamber while the earlier chambers helped regulate buoyancy in the water column. Their rapid evolution and widespread distribution make ammonites among the most important fossils for dating and correlating Jurassic rock layers.
Sonninia is a well-known Bajocian ammonite genus and is especially associated with the early Middle Jurassic ammonite faunas of Europe. Sonninia ammonites are commonly placed within the family Sonniniidae, superfamily Hammatoceratoidea, and order Ammonitida. They are highly valued by collectors because of their distinctive Jurassic appearance, scientific importance, and strong association with the Inferior Oolite successions of Somerset and Dorset.
Sonninia specimens often show moderately evolute coiling, where the earlier whorls remain partly visible rather than being completely covered by later shell growth. Many examples display bold ribbing across the flanks, with ornamentation that may vary during growth. Depending on preservation and maturity, the shell can appear compressed to moderately inflated, with a strong profile and classic Bajocian ammonite character.
Inferior Oolite Group Geology
This ammonite comes from the Inferior Oolite Group, one of Britain’s most famous Middle Jurassic fossil-bearing rock units. Despite the name “Inferior”, the term refers to its position below the Great Oolite in the geological succession, not to the quality of the fossils. The Inferior Oolite is well known for producing ammonites, brachiopods, bivalves, gastropods, echinoids, corals, and other marine fossils.
At the time this ammonite lived, the area now represented by Bruton in Somerset formed part of a shallow marine carbonate shelf. Warm Jurassic seas covered the region, depositing lime-rich sediments, shell debris, oolitic grains, and marine muds across the sea floor. Over millions of years these sediments hardened into limestone and related rocks, preserving the remains of marine organisms such as ammonites.
The Cole Syncline is an important geological structure in the Bruton area, where folded Jurassic rocks expose parts of the Inferior Oolite succession. Fossils from this region are sought after because they combine a classic British locality with scientifically useful Middle Jurassic stratigraphy.
Bajocian Age and Scientific Interest
The Bajocian Stage is part of the Middle Jurassic Period and is especially important in ammonite biostratigraphy. Ammonites evolved quickly during this time, producing distinctive species and lineages that are useful for identifying and comparing rock layers across different regions.
A specimen labelled as Sonninia cf. sowerbyi from the Bajocian of Somerset has strong palaeontological interest because Sonninia is closely associated with early Bajocian ammonite assemblages. Fossils of this type help illustrate the diversity of marine cephalopods that lived in the Jurassic seas of western Europe and are particularly desirable for collectors building a labelled British ammonite collection.
Collectable British Jurassic Ammonite
This fossil is ideal for collectors of UK fossils, Jurassic ammonites, natural history specimens, and educational geology displays. Its combination of named genus, comparative species identification, Middle Jurassic age, Inferior Oolite Group provenance, and Somerset locality gives it stronger collecting appeal than an unidentified ammonite.
The fossil also has excellent regional interest, coming from Bruton, Cole Syncline, Somerset, an area connected with Britain’s rich Jurassic fossil record. Whether displayed as part of a fossil cabinet, used as an educational specimen, or added to a specialist ammonite collection, this Sonninia ammonite provides an attractive and meaningful example of ancient marine life.
Authenticity and Presentation
This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card. The specimen has been carefully selected, and the photograph shows the actual fossil you will receive. Full sizing can be seen in the photo.
As a genuine Sonninia cf. sowerbyi ammonite from the Inferior Oolite Group of Bruton, Somerset, this fossil offers a desirable and scientifically interesting example of Middle Jurassic marine life from one of Britain’s classic ammonite-bearing geological successions.
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