Xipheroceras Fossil Ammonite Dogtooth Calcite Crystals Lyme Regis Jurassic Coast Dorset UK Genuine Specimen Certificate

Xipheroceras Fossil Ammonite with Dogtooth Calcite – Lyme Regis Jurassic Coast

This exceptional Xipheroceras fossil ammonite is beautifully preserved with striking dogtooth calcite crystals, collected from the famous Black Ven Marls of the Lower Lias on the Jurassic Coast at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK.

The specimen was discovered by our own team members, Alister and Alison, on 28 February 2025 and has been professionally cleaned, prepped and treated by Alison to ensure excellent presentation and long-term stability.

This fossil includes a Certificate of Authenticity lifetime guarantee generic card. The photographs show the exact specimen you will receive, and full sizing details are clearly provided in the listing images.

Fossil Identification – Xipheroceras Ammonite

Xipheroceras is an Early Jurassic ammonite, part of the extinct marine cephalopods that thrived in Jurassic seas. It belongs to:

• Order: Ammonitida

• Suborder: Ammonitina

• Superfamily: Eoderoceratoidea

• Family: Eoderoceratidae

This genus is characteristic of the Sinemurian Stage of the Early Jurassic, approximately 199–190 million years ago. Ammonites such as Xipheroceras are important index fossils, widely used in stratigraphy to date and correlate Lower Lias marine sediments along the Dorset coast.

Geological Setting – Black Ven Marls, Lower Lias

The Black Ven Marls are part of the Lower Lias Group, deposited in a shallow marine environment during the Early Jurassic. These fine-grained clays and marls formed under relatively low-energy conditions, allowing marine organisms to settle and be rapidly buried in soft muds.

Stonebarrow Cliff and the Lyme Regis coastline are internationally renowned for fossil preservation and form part of the UNESCO World Heritage Jurassic Coast. This area provides one of the most continuous and scientifically significant records of Early Jurassic marine life in the world.

The ammonites preserved here represent a thriving ancient ecosystem that also included bivalves, belemnites, crinoids, and marine reptiles.

Dogtooth Calcite Crystal Association

What makes this specimen especially desirable is the presence of dogtooth calcite crystals. Dogtooth calcite refers to sharp, scalenohedral calcite formations that grow in cavities within sedimentary rocks during later mineralisation.

These crystals formed long after the ammonite was fossilised, when mineral-rich groundwater circulated through fractures and voids in the rock. The calcite precipitated into distinctive pointed crystal clusters, creating a beautiful natural contrast between fossil shell and sparkling mineral growth.

This combination of fossil and crystal mineralisation is highly sought after by collectors, as it represents both palaeontological and mineralogical interest in one specimen.

Morphology and Notable Features

Xipheroceras ammonites are known for their evolute coiling, where earlier whorls remain visible, and for strong ribbing patterns across the shell. The ribs often bifurcate as they cross the flanks, giving the ammonite a textured and distinctive appearance.

The preserved detail in this specimen highlights the natural shell morphology while the calcite adds an eye-catching crystalline accent.

Discovery, Preparation and Authenticity

This fossil was personally discovered by Alister and Alison on 28 February 2025 at Stonebarrow Cliff. Alison has carefully cleaned, stabilised, and prepared the specimen, ensuring that both the ammonite detail and calcite crystals are displayed at their best while preserving the original matrix context.

This Xipheroceras Fossil Ammonite with Dogtooth Calcite Crystals is a genuine Jurassic Coast specimen and includes a Certificate of Authenticity lifetime guarantee generic card. The fossil shown in the photographs is the exact piece you will receive, carefully chosen for its preservation, locality significance, and unique mineral association.

A Lyme Regis ammonite with calcite crystal growth like this is a rare and highly collectible example of Early Jurassic marine history combined with later geological mineral formation.