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

Description

Genuine Arnioceras Multi Block Fossil Ammonites

This exceptional specimen is a multi block of Arnioceras ammonite fossils preserved in the Black Ven Marls, Lower Lias, from the world-renowned Jurassic Coast at Black Ven, Lyme Regis, Dorset, UK. Dating back to the Early Jurassic Period, approximately 200 million years ago, this fossil block captures the beauty and scientific importance of one of the most famous fossil localities on Earth. Each ammonite within the block is naturally preserved in its original matrix, offering a window into ancient seas and the marine life that thrived in them.

Discovered on 14 September 2025 by our team members Alister and Alison, and carefully cleaned, prepped, and treated by Alison, this specimen is presented exactly as found, with professional preparation ensuring the ammonites are showcased in the best possible condition. The accompanying photos show the actual fossil you will receive, with a 1 cm scale cube for reference. Every piece we sell comes with a Certificate of Authenticity for your peace of mind.

Geological Context and Formation

The Black Ven Marls are part of the Lower Lias succession, a series of marine sediments deposited during the Early Jurassic. These rocks are exposed on the Jurassic Coast UNESCO World Heritage Site, one of the richest fossil-bearing coastlines in the world.

Arnioceras ammonites are typically associated with the lower Sinemurian Stage of the Jurassic, an interval that provides critical evidence for biostratigraphy and evolutionary history. The marl and shale deposits at Black Ven were laid down in shallow seas under low-energy conditions, ideal for the preservation of ammonites and other marine life.

Species Information – Arnioceras

Arnioceras belongs to the order Ammonitida, superfamily Eoderoceratoidea, and family Arietitidae. These ammonites are distinguished by their evolute shells, strong ribbing, and prominent keel, giving them a bold and recognisable appearance. Their ribbed ornamentation and coiling structure make them excellent index fossils, used by palaeontologists to date and correlate Lower Jurassic strata across Europe.

Arnioceras ammonites were nektonic predators, swimming actively in the shallow Jurassic seas and feeding on small invertebrates. Their evolutionary significance and wide distribution make them an essential genus for understanding ammonite diversity and Early Jurassic marine life.

Fossil Features and Preservation

This multi block specimen preserves several Arnioceras ammonites together in their natural matrix, providing a striking and scientifically important association. The ammonites display clear ribbing and well-defined coiling, with excellent preservation of their shell morphology.

Some individuals in the block are partially filled with calcite, giving them an attractive crystalline contrast against the darker marlstone. The grouping of multiple ammonites in one slab demonstrates how these animals often accumulated naturally on the seafloor, offering valuable insight into their depositional environment.

Scientific and Collector Value

Arnioceras ammonites are significant as index fossils, marking specific intervals within the Sinemurian Stage. Their presence in this specimen makes the block not only a beautiful display piece but also a resource of stratigraphic value. Multi block specimens are highly prized because they preserve palaeoecological associations, showing ammonites as they were naturally deposited rather than as isolated individuals.

For collectors, this fossil offers a rare chance to own a genuine Jurassic Coast ammonite block with both scientific and aesthetic appeal. Its provenance from Black Ven, a site famously associated with fossil hunting history since Mary Anning’s discoveries, further enhances its desirability.

A Rare Jurassic Coast Fossil Block

This Arnioceras multi block ammonite fossil from the Black Ven Marls of Lyme Regis is a true showcase of Britain’s palaeontological heritage. It combines scientific importance, natural beauty, and guaranteed authenticity, making it ideal for collectors, educators, or anyone passionate about Earth’s ancient history.

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