Xipheroceras Calcite Ammonite Fossil Jurassic Lyme Regis Dorset UK Lower Lias

Description

Authentic Xipheroceras Calcite Ammonite from the Jurassic Coast

Offered here is a genuine Xipheroceras calcite ammonite fossil, recovered from the classic Black Ven Marls at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, one of the most celebrated fossil localities on England’s Jurassic Coast. The specimen shown in the photographs is the exact fossil you will receive, carefully selected for preservation quality and visual appeal. Full sizing details are shown in the photos for complete transparency.

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

Discovery, Provenance, and Preparation

This specimen was discovered by our own team members, Alister and Alison, on 18 December 2025 during fieldwork at Stonebarrow Cliff. Following collection, the ammonite was cleaned, professionally prepared, and stabilised by Alison, ensuring the fossil is presented in its best natural condition while preserving all diagnostic features. Team-collected fossils with documented preparation history are highly valued, offering a clear and traceable provenance from discovery to display.

Geological Formation and Age

The fossil originates from the Lower Lias Group, dating to 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 deposited in a shallow epicontinental sea that covered southern Britain. Stonebarrow Cliff is internationally recognised for its abundance of ammonites that form the backbone of Early Jurassic biostratigraphy and palaeoenvironmental research.

Fossil Species and Scientific Context

Xipheroceras is an Early Jurassic ammonite genus belonging to the Order Ammonitida, Superfamily Eoderoceratoidea, and Family Eoderoceratidae. It represents an important group of ammonites that diversified rapidly following the end-Triassic extinction. Xipheroceras is well documented from the Lower Lias of Dorset and is frequently referenced in scientific literature due to its distinctive morphology and stratigraphic significance within Sinemurian ammonite assemblages.

Morphology and Calcite Preservation

This specimen displays classic planispiral coiling with relatively open whorls and clearly defined ribbing across the flanks. Rib strength and spacing vary subtly through growth, illustrating natural ontogenetic development. The ammonite has undergone calcite mineralisation, which enhances fine surface detail and gives the fossil a pale, crystalline appearance that contrasts attractively with the darker marl matrix. Preservation quality allows the shell ornamentation, proportions, and overall form to be clearly appreciated from multiple angles.

Depositional Environment

During the Early Jurassic, the Charmouth and Lyme Regis area lay beneath a warm, shallow marine environment rich in ammonites, belemnites, fish, and marine reptiles. Fine sediments accumulated slowly on the sea floor, allowing ammonite shells to be rapidly buried after death. Periodic low-oxygen conditions reduced scavenging and disturbance, contributing to the excellent preservation of ammonites within the Black Ven Marls. These conditions are responsible for the exceptional fossil record that makes the Jurassic Coast globally significant.

Collecting, Display, and Educational Value

This Xipheroceras calcite ammonite fossil is ideal for serious fossil collectors, educational collections, museum displays, or refined interior presentation. Its classic British Jurassic provenance, clear taxonomic identification, team-documented discovery, and strong visual presence make it both scientifically informative and aesthetically appealing. Ammonites from Stonebarrow Cliff are increasingly sought after due to their geological importance and consistent quality. Each specimen we offer is individually selected to ensure you receive an authentic and carefully curated piece of Early Jurassic marine history from one of the world’s most important fossil coastlines.