Description
Genuine Procerites tmetolobus Ammonite Fossil
This genuine Procerites tmetolobus ammonite is a carefully selected British fossil from the Zigzag Bed at Burstock, near Broadwindsor, Dorset, UK. Dating from the Bathonian Stage of the Middle Jurassic, it represents an extinct marine cephalopod that inhabited the seas covering southern Britain during one of the most significant periods in ammonite evolution.
The photograph shows the actual fossil specimen you will receive. Full sizing and proportions can be seen in the accompanying photographs, allowing the specimen’s preservation, natural shape, surface detail and matrix to be assessed before purchase.
Fossil Species and Ammonite Morphology
Procerites tmetolobus belongs to a group of planispirally coiled ammonites characterised by their chambered shells and pronounced external ornamentation. Species assigned to Procerites typically possess an evolute to moderately evolute shell, meaning that the earlier whorls remain at least partly visible within the open central umbilicus.
The shell ornament generally consists of clearly defined radial ribs. These may begin as stronger primary ribs near the umbilical margin before dividing into finer secondary ribs across the flanks and outer part of the whorl. The combination of whorl shape, rib spacing, rib division and umbilical proportions is important when comparing and identifying Middle Jurassic ammonites.
Ammonites were active marine molluscs related to modern squid, cuttlefish, octopuses and nautiluses. Their shells were internally divided into chambers by curved walls called septa. The animal occupied the final body chamber, while the earlier chambers formed a buoyancy system connected by a narrow tube known as the siphuncle. This allowed the ammonite to regulate its position within the water column.
Middle Jurassic Bathonian Geology
This fossil comes from rocks assigned to the Bathonian Stage of the Middle Jurassic Period. The Bathonian lasted from approximately 168 to 166 million years ago and was named after the historic city of Bath in southwest England, where Jurassic strata of this age are particularly well developed.
During the Bathonian, the area that is now Dorset lay beneath a warm, shallow sea. Marine sediments accumulated across an extensive shelf environment, preserving the remains of ammonites and other organisms within layers of limestone, marl and related sedimentary rocks. Conditions varied through time as sea level, sediment supply and water depth changed, producing distinct beds that can be recognised and correlated between different exposures.
The Zigzag Bed is named for its association with the characteristic Bathonian ammonite succession traditionally linked with the Zigzag biozone. Ammonites are especially valuable in this type of geological study because their species evolved relatively rapidly and were widely distributed through Jurassic seas. Their remains therefore help palaeontologists compare rocks of similar age across different regions.
Burstock, Broadwindsor, Dorset Provenance
Burstock lies near Broadwindsor in west Dorset, an area renowned for its richly fossiliferous Jurassic geology. Although Dorset is most famous for the coastal exposures of the Jurassic Coast, important inland locations also preserve sedimentary units containing ammonites and other marine fossils.
A precisely recorded locality adds considerable scientific and historical interest to a fossil. This specimen retains the important provenance of Burstock, near Broadwindsor, together with its identification as Procerites tmetolobus and its origin from the Zigzag Bed. It is therefore more informative than an ammonite supplied without stratigraphic or geographical details.
Fossilisation and Preservation
Following the ammonite’s death, its shell settled onto or became incorporated within the Jurassic seabed. Burial by sediment protected portions of the shell from complete destruction. Over millions of years, the surrounding sediment was compacted and cemented into rock, while the ammonite shell was preserved as original material, replacement minerals, an internal mould or a combination of these forms.
Natural fossils commonly display small areas of weathering, incomplete shell, mineral-filled fractures, matrix attachment or slight distortion caused by geological pressure. These features are part of the specimen’s history and distinguish a genuine fossil from a manufactured reproduction.
A Collectable British Jurassic Fossil
This Procerites tmetolobus ammonite is an appealing specimen for collectors of British fossils, Jurassic ammonites, Dorset geology and natural-history objects. Its named species, Bathonian age, Zigzag Bed stratigraphy and documented Burstock provenance make it suitable for a fossil collection, educational display, geological cabinet or distinctive natural-history gift.
The fossil has been individually chosen, and the listing photographs show the exact specimen offered for sale rather than a generic example. Full sizing is shown in the photographs.
This is a 100% genuine fossil specimen and includes a generic Certificate of Authenticity card with a lifetime guarantee.
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