Xipheroceras Multi Calcite Ammonite Fossil Block Jurassic Lyme Regis Dorset UK Lower Lias Black Ven

Description

Authentic Multi-Ammonite Fossil Block from the Jurassic Coast

Offered here is a striking Xipheroceras multi calcite ammonite fossil block with Promicroceras, recovered from the famous Black Ven Marls at Black Ven, Charmouth, Lyme Regis, Dorset, along England’s internationally renowned Jurassic Coast. This is a carefully chosen natural fossil block containing multiple ammonites preserved together within the original matrix. The photographs show the exact specimen you will receive, selected for clarity, composition, and scientific interest. Full sizing details are shown in the photos.

This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card, providing confidence in provenance and long-term collectability.

Geological Formation and Age

This ammonite block originates from the Lower Lias Group, deposited during the Early Jurassic Period, approximately 199–191 million years ago, within the Sinemurian Stage. The Black Ven Marls are composed of fine-grained marine mudstones and marls laid down in a shallow epicontinental sea that covered much of southern Britain. This formation is globally significant for its rich ammonite fauna and its importance in Jurassic stratigraphy. Constant coastal erosion at Black Ven continues to reveal exceptionally preserved fossils, making this locality one of the most productive and historically important fossil sites in the world.

Fossil Type, Species, and Scientific Context

This specimen features multiple ammonites preserved together, dominated by Xipheroceras, with associated Promicroceras individuals visible within the block. Xipheroceras and Promicroceras are Early Jurassic ammonites belonging to the Order Ammonitida and are characteristic elements of Lower Lias marine faunas. Promicroceras is widely recognised as an index fossil, closely associated with the Promicroceras biozone, making blocks such as this especially valuable for understanding Early Jurassic biostratigraphy. The presence of multiple genera within a single block provides insight into contemporaneous ammonite assemblages.

Morphology and Preservation

The ammonites within this block exhibit classic planispiral coiling, with clearly defined whorls and ribbing preserved through calcite mineralisation. Xipheroceras is known for its more elongated, evolute shell form and pronounced ribbing, while Promicroceras typically displays tighter coiling with bold, evenly spaced ribs. The calcite preservation enhances surface detail and contrast against the darker marl matrix, allowing individual shells to stand out clearly. This style of preservation not only improves durability but also creates a visually impressive natural display piece.

Depositional Environment

During the Early Jurassic, the Lyme Regis and Charmouth area lay beneath a warm, shallow marine environment with relatively calm conditions. Fine sediments accumulated slowly on the sea floor, allowing shells to be buried rapidly after death. Periodic low-oxygen conditions reduced scavenging and bioturbation, enabling multiple ammonites to be preserved together within the same sedimentary horizon. Such conditions are responsible for the fossil-rich nature of the Black Ven Marls and the frequent occurrence of multi-fossil blocks.

Collecting, Display, and Educational Value

This Xipheroceras multi calcite ammonite fossil block with Promicroceras is ideal for serious fossil collectors, educational collections, museum displays, or statement interior presentation. The combination of multiple ammonites, classic British provenance, and clear geological context makes this specimen both scientifically informative and visually striking. Multi-ammonite blocks from Lyme Regis are particularly sought after due to their natural composition and strong connection to the history of palaeontology. Each specimen we offer is individually selected, ensuring you receive a genuine and carefully curated piece of Early Jurassic marine history from one of the world’s most celebrated fossil localities.