Promicroceras Calcite Ammonite Fossil Jurassic Coast Black Ven Lyme Regis Dorset UK

Description

Promicroceras Calcite Ammonite Fossil

This listing is for a genuine Promicroceras Calcite Ammonite Fossil from the Black Ven Marls, Lower Lias Formation, Black Ven, Lyme Regis, Dorset, UK, one of the most celebrated fossil localities in the world and part of the UNESCO Jurassic Coast World Heritage Site. Dating to the Early Jurassic (Sinemurian stage, around 199–196 million years ago), this specimen represents one of the most scientifically important ammonite genera of the Lower Jurassic. It was discovered by our own team members, Alister and Alison, on 14th September 2025, and has been carefully cleaned, prepped, and treated by Alison to preserve its natural form and enhance its fine details.

Geological Context – Black Ven Marls, Lower Lias

The Black Ven Marls are world-renowned for their fossil richness, producing countless ammonites, belemnites, crinoids, and marine reptiles. These deposits were laid down in a shallow marine environment, where fine muds and calcareous sediments settled, burying marine organisms rapidly and preserving them in exquisite detail. Fossils from this locality are highly sought after by collectors and researchers due to their abundance, beauty, and scientific importance. The calcite replacement seen in this Promicroceras specimen is typical of the region and adds to its aesthetic and structural value.

Species Profile – Promicroceras

The genus Promicroceras belongs to the Order Ammonitida, Superfamily Psiloceratoidea, and Family Promicroceratidae. These small ammonites are among the most iconic fossils of the Lower Jurassic and are often used as index fossils for the Early Sinemurian stage. They are characterised by their tightly coiled, evolute shells with narrow whorls and distinct ribbing, which creates a delicate and attractive spiral pattern. Despite their small size, Promicroceras ammonites are of immense paleontological value, helping geologists to date and correlate Lower Jurassic rock sequences with precision.

Morphology and Preservation

This specimen displays the classic features of Promicroceras ammonites, with its fine ribbing, clearly defined coiling, and compact spiral structure. The preservation in calcite has replaced the original aragonite shell material, giving the fossil strength and a natural crystalline appearance. Such preservation highlights the intricate ribbing and allows collectors to appreciate the ammonite’s detailed morphology. Its small yet highly detailed form makes it a superb example of Early Jurassic ammonite diversity.

Scientific and Stratigraphic Importance

Promicroceras fossils are the defining feature of the Promicroceras planicosta biozone, one of the earliest ammonite zones of the Sinemurian. Their abundance and wide distribution across Europe make them invaluable to biostratigraphy, enabling geologists to reconstruct ancient marine environments and refine the geological timescale. Their evolutionary significance lies in their role as one of the earliest fully developed ammonite lineages after the Triassic–Jurassic extinction, showcasing the rapid diversification of these cephalopods in Early Jurassic seas.

Responsible Collection and Preparation

This fossil was responsibly collected from the Black Ven foreshore and prepared by Alison using skilled techniques to bring out its natural beauty without compromising its integrity. Ethical and careful handling ensures that the fossil retains both its scientific and aesthetic value, while maintaining the natural heritage of the Jurassic Coast.

Authenticity and Presentation

All of our fossils are 100% genuine specimens and are accompanied by a Certificate of Authenticity. The photographs show the exact specimen you will receive, not a stock image. A 1 cm scale cube is included in the photos for accurate size reference. This Promicroceras ammonite was hand-selected for its quality and clarity, making it an ideal specimen for collectors, educators, or display in any natural history setting.

This Promicroceras Calcite Ammonite Fossil from the Black Ven Marls of Lyme Regis, Dorset, UK, is a scientifically important and visually striking specimen, representing one of the most iconic ammonites of the Early Jurassic seas.