Promicroceras Calcite Ammonite Fossil Jurassic Lyme Regis Dorset UK Lower Lias Black Ven Marls

Description

Authentic Promicroceras Ammonite from the Jurassic Coast

Offered here is a genuine Promicroceras calcite ammonite fossil from the world-famous Black Ven Marls, Black Ven, Lyme Regis, Dorset, situated along England’s internationally recognised Jurassic Coast. The photographs show the exact specimen you will receive, carefully selected for its preservation, clarity, and scientific interest. Full sizing details are provided in the images to allow accurate assessment prior to purchase.

All of our fossils are 100% genuine specimens and are supplied with a Certificate of Authenticity, ensuring complete confidence in provenance and authenticity.

Geological Formation and Age

This specimen 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 consist of fine-grained marine mudstones and marls laid down in a shallow epicontinental sea that once covered southern Britain. This geological unit is internationally important due to its exceptional fossil abundance and its key role in defining Early Jurassic stratigraphy. Black Ven is particularly notable for its continuous exposures and long history of palaeontological study, making fossils from this locality both scientifically reliable and historically significant.

Fossil Type, Species, and Scientific Classification

Promicroceras is a classic Early Jurassic ammonite genus belonging to the Order Ammonitida, Superfamily Eoderoceratoidea, and Family Echioceratidae. This genus is widely recognised as an index fossil, meaning it is used extensively to date and correlate Lower Lias marine sediments. Promicroceras is characteristic of the Promicroceras biozone, a key biostratigraphic interval within the Sinemurian Stage, making specimens from this genus particularly valuable to collectors with an interest in geology and palaeontology.

Morphology and Preservation

This ammonite displays the distinctive evolute shell coiling typical of Promicroceras, with earlier whorls clearly visible and a relatively wide umbilicus. The shell surface shows strong, well-defined ribbing, often gently curved and occasionally bifurcating across the flanks, producing a bold and recognisable appearance. The fossil has undergone natural calcite mineralisation, which enhances durability while preserving fine morphological detail. This calcite infill highlights the original shell structure and adds visual contrast, making the specimen especially attractive for display.

Depositional Environment

During the Early Jurassic, the Lyme Regis area lay beneath a warm, shallow marine environment with calm water conditions. Fine sediments settled slowly on the sea floor, allowing ammonite shells to be rapidly buried after death. Periodic low-oxygen conditions reduced scavenging and bioturbation, contributing to the excellent preservation seen in ammonites from the Black Ven Marls. These environmental conditions are key to the exceptional fossil record preserved along the Jurassic Coast.

Collecting, Display, and Educational Value

This Promicroceras calcite ammonite fossil is ideal for private collectors, educational use, museum displays, or refined home presentation. Its classic British provenance, clear stratigraphic placement, and attractive preservation make it both scientifically meaningful and visually striking. Each specimen we offer is individually selected, ensuring you receive a carefully curated and authentic piece of Early Jurassic marine history from one of the most important fossil localities in the world.