Xipheroceras Calcite Ammonite Fossil Cut Base 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 with a cut base, collected from the classic Black Ven Marls at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, on England’s world-famous Jurassic Coast. This specimen has been carefully selected for its preservation quality, strong morphological definition, and natural visual balance. The photographs show the exact fossil you will receive, and full sizing details are provided in the photos for complete clarity.

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 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 formed in a shallow epicontinental sea that once covered much of southern Britain. Stonebarrow Cliff is one of the most productive and scientifically important Lower Jurassic exposures in Europe, renowned for its abundance of ammonites used in Jurassic stratigraphy.

Fossil Type, Species, and Scientific Context

Xipheroceras is an Early Jurassic ammonite genus belonging to the Order Ammonitida, Superfamily Eoderoceratoidea, and Family Eoderoceratidae. It is closely associated with Lower Lias ammonite assemblages and is well documented in British Jurassic palaeontology. Xipheroceras plays an important role in understanding early ammonite evolution following the end-Triassic extinction and is valued for its distinctive shell form and stratigraphic significance.

Morphology and Calcite Preservation

This specimen displays the characteristic planispiral coiling of Xipheroceras, with relatively open whorls and pronounced ribbing across the flanks. The ribs often show subtle changes in strength and spacing as the shell grows, reflecting ontogenetic development. The ammonite has undergone calcite mineralisation, enhancing fine surface detail and giving the fossil a pale, crystalline appearance that contrasts beautifully with the darker marl matrix.

The cut base has been professionally prepared to allow the ammonite to stand upright securely, making it ideal for cabinet, shelf, or desk display without additional supports.

Depositional Environment

During the Early Jurassic, the Charmouth and Lyme Regis region 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 underpin the global importance of the Jurassic Coast fossil record.

Collecting, Display, and Educational Value

This Xipheroceras calcite ammonite fossil with cut base is ideal for serious fossil collectors, educational collections, museum displays, or refined interior presentation. Its classic British Jurassic provenance, clear taxonomic identification, and practical display preparation make it both scientifically informative and visually striking. Ammonites from Stonebarrow Cliff are increasingly sought after, particularly well-prepared examples suitable for display. 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.