Arnioceras Multi Block Fossil Ammonites Black Ven Marls Lower Lias Jurassic Coast Black Ven Lyme Regis Dorset UK

Description

Authentic Arnioceras Multi Block Ammonite Fossils from Lyme Regis

This listing is for a genuine Arnioceras multi block of fossil ammonites, sourced from the world-famous Black Ven Marls, Lower Lias, at Black Ven, Lyme Regis, Dorset, UK. These ammonites date back to the Lower Jurassic, approximately 200 million years ago, and represent an important part of Britain’s geological heritage. The exact specimen photographed is the one you will receive, with a 1 cm scale cube included for accurate size reference.

The specimen was discovered on 14 September 2025 by our team collectors, Alister and Alison, and has been expertly cleaned, prepped, and treated by Alison to reveal and preserve its natural features. As with all our fossils, it is supplied with a Certificate of Authenticity, ensuring it is a 100% genuine specimen with secure provenance.

Geological Context and Age

The Black Ven Marls form part of the Lower Lias deposits exposed along the Dorset section of the Jurassic Coast, a UNESCO World Heritage Site. These deposits represent sedimentary layers formed in shallow marine environments during the Early Jurassic. Fine muds and silts settled at the sea floor, burying and preserving ammonites, marine reptiles, belemnites, and other marine organisms.

Ammonites like Arnioceras are crucial index fossils used in Jurassic biostratigraphy. Their limited stratigraphic range allows geologists to date specific horizons with great accuracy. The presence of multiple individuals in a single block makes this specimen particularly valuable as a record of ancient ammonite assemblages.

Species Information – Arnioceras

Arnioceras is an extinct genus of ammonites belonging to the order Ammonitida, superfamily Eoderoceratoidea, and family Arietitidae. These ammonites are characterised by relatively evolute shells, with whorls that do not overlap extensively, allowing earlier coils to remain visible. Their ribbing is typically strong and well developed, giving the shell a strikingly ornamented appearance.

In terms of palaeoecology, Arnioceras is thought to have been an active nektonic predator, inhabiting shallow marine environments and feeding on smaller invertebrates. Its morphological features make it distinct among Lower Jurassic ammonites and contribute to its importance in defining key ammonite zones.

Fossil Features and Preservation

This multi block specimen contains several ammonites preserved together within the marlstone matrix. The shells display ribbing and coiling patterns typical of Arnioceras, offering a strong visual impression of the genus. The preservation in marl ensures fine details are visible, while the natural compression of the sediments provides authenticity and scientific context.

The preparation process has highlighted the ammonites without overworking the stone, allowing the fossils to retain their natural integrity. The block composition makes this specimen both scientifically informative and highly attractive for display, showing ammonites in association as they were originally deposited.

Collector and Scientific Importance

Arnioceras is highly significant in the study of Lower Jurassic stratigraphy and ammonite evolution. Its restricted occurrence in the Early Jurassic makes it a reliable guide fossil for correlation across Europe. A multi block specimen such as this provides not just a single ammonite but a broader representation of an ancient ammonite bed, reflecting palaeoecological conditions of the time.

For collectors, this fossil is a rare opportunity to own a specimen with both visual appeal and strong scientific value. Its provenance from Black Ven, one of the most famous fossil sites in the world, enhances its desirability.

A Unique Jurassic Fossil from the Black Ven Marls

This Arnioceras multi block of fossil ammonites is an authentic and well-prepared specimen from the Lower Jurassic of Dorset. With its combination of beauty, scientific importance, and provenance, it makes a perfect addition for fossil collectors, educators, or anyone fascinated by natural history. Supplied with a Certificate of Authenticity, it stands as both a stunning display fossil and a scientifically valuable piece of Jurassic heritage.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.