5.5″ Brasilia Fossil Ammonite with Cut Base Bajocian Jurassic Dorset UK Genuine Horn Park Ammonite Specimen with Certificate of Authenticity

Description

Authentic 5.5″ Brasilia Fossil Ammonite with Cut Base

This exceptional specimen is a 5.5-inch Brasilia ammonite fossil from the Bajocian stage of the Middle Jurassic, collected at the historically important Horn Park site in Dorset, United Kingdom. The ammonite has been carefully prepared and features a cut base, allowing it to be displayed upright as a natural geological showcase. The photographs show the actual fossil you will receive, with a 1 cm scale cube and rule squares included for precise sizing. Every piece we supply is 100% genuine and accompanied by a Certificate of Authenticity.

Geological Context – Bajocian of Horn Park

The Bajocian stage, approximately 170.3–168.3 million years ago, is a key interval of the Middle Jurassic, marked by the flourishing and diversification of ammonites. Horn Park Quarry in Dorset is one of Britain’s most famous Bajocian fossil localities, recognised for its abundance of ammonites and its importance in stratigraphy. Fossils from this site were deposited in shallow marine environments, where warm seas encouraged the proliferation of diverse marine organisms. Over millions of years, the calcareous sediments lithified into fossil-bearing limestone, preserving ammonites in remarkable detail.

Species Overview – Brasilia Ammonites

The genus Brasilia belongs to the order Ammonitida, superfamily Hildoceratoidea, and family Graphoceratidae. Known primarily from Bajocian deposits, Brasilia ammonites are distinguished by their broad, evolute shells and well-defined ribbing. Their presence in Horn Park and other Bajocian localities makes them useful for biostratigraphic correlation, helping palaeontologists to divide Jurassic time into distinct zones. The genus highlights the evolutionary transitions that occurred within ammonites during the Middle Jurassic, a period of great diversity and radiation.

Morphological Features

This specimen of Brasilia ammonite displays the classic features of the genus. The whorls are broad and evolute, with earlier coils still partially visible. Strong, radiating ribs cross the flanks of the shell and bifurcate before reaching the venter, creating a striking pattern typical of Bajocian ammonites. The cut base provides additional functionality, enabling the fossil to be displayed freestanding, making it ideal for both study and decorative presentation. The preservation of ribbing and overall shell form makes this an outstanding example of Jurassic ammonite morphology.

Scientific and Collectible Importance

Brasilia ammonites are not only visually appealing but also scientifically significant. They are often associated with particular biozones within the Bajocian stage, such as the Garantiana Zone, allowing precise dating of Jurassic rocks. For collectors, this fossil represents a combination of aesthetic value, size, and stratigraphic importance. Its cut base adds to its uniqueness, making it as suitable for display in a collection cabinet or desk as for use in educational and research settings.

Provenance and Guarantee

This ammonite was collected from Horn Park in Dorset, a quarry renowned for its Bajocian ammonites and long recognised in British palaeontology. Carefully chosen for its quality, preservation, and natural beauty, this specimen comes with a Certificate of Authenticity guaranteeing that it is 100% genuine. The exact fossil in the photographs is the one you will receive, ensuring complete transparency.

A Rare Jurassic Fossil with Display Base

This 5.5-inch Brasilia ammonite with cut base from Horn Park, Dorset is a striking specimen that combines scientific importance with display quality. Its size, preservation, and provenance from one of the UK’s most famous fossil localities make it a valuable addition to any fossil collection, offering a tangible link to the marine ecosystems of the Jurassic seas.