Charmouth Ammonite Impression Fossil Lower Lias Jurassic Coast Black Ven Dorset UK

Description Overview & Authenticity This listing offers a genuine Charmouth ammonite impression fossil from the world-famous Black Ven Marls, located on the Jurassic Coast at Black Ven, Lyme Regis, Dorset, UK. This is a carefully chosen natural fossil impression, preserved within the original Jurassic sediment and presented exactly as shown in the photographs. The images show an example of the actual specimen you will receive, ensuring complete clarity and confidence when purchasing. The fossil is supplied with a Certificate of Authenticity, including a lifetime guarantee of genuineness, provided on a generic authenticity card, making it a secure and permanent addition to any fossil collection. Geological Context The fossil originates from the Lower Lias Group, dating to the Early Jurassic Period, approximately 195–190 million years ago. During this time, southern Britain was submerged beneath a shallow tropical sea rich in marine life. Fine-grained marls and mudstones were deposited on the seabed in relatively calm conditions, ideal for capturing delicate fossil impressions. Black Ven is internationally recognised for its scientific importance and continuous coastal erosion, which regularly exposes new fossil-bearing layers. Fossils from this locality have been studied for centuries and played a foundational role in the early development of palaeontology in Britain. Fossil Type & Formation This specimen is an ammonite impression, also known as a natural mould, formed when the original aragonite shell dissolved after burial, leaving a detailed negative imprint preserved in the surrounding sediment. While the original shell material is no longer present, the impression retains the full outline, coiling pattern, and surface ornamentation of the ammonite. Such impressions are highly valued for their clarity and for the insight they provide into fossilisation processes, representing a different but equally important mode of preservation compared to shell-bearing fossils. Morphology & Visual Features The ammonite impression displays the classic planispiral coiling typical of Jurassic ammonites, with clearly defined whorls and rib patterns visible across the fossil surface. Growth lines and ribbing radiate outward from the centre, allowing the shell’s original form to be easily interpreted. The contrast between the impression and the surrounding marl matrix enhances visibility, making this specimen both educational and visually striking. Impression fossils such as this are particularly useful for studying shell morphology, as they often preserve external features with exceptional fidelity. Depositional Environment & Palaeoecology Ammonites were free-swimming marine cephalopods, occupying a vital role in Early Jurassic marine ecosystems. After death, shells settled onto the soft seabed. Burial within fine sediment limited disturbance, while chemical conditions later caused the shell material to dissolve, leaving behind the preserved impression. The Lower Lias marine environment was rich in biodiversity, and ammonites like this one are key index fossils used to interpret Jurassic sea levels, climate, and evolutionary change. Collectability & Display Charmouth and Lyme Regis ammonite fossils are among the most desirable British fossils due to their provenance, historical significance, and scientific value. This ammonite impression is ideal for collectors, educational displays, museums, or as a distinctive geological gift. Full sizing details can be found in the photographs. As a genuine Jurassic fossil from one of the most famous fossil localities in the world, this specimen offers a tangible connection to deep geological time and the rich natural heritage of the Jurassic Coast.