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

Description

Genuine Promicroceras Ammonite from the Jurassic Coast

This listing offers a genuine Promicroceras calcite ammonite fossil collected from the renowned Black Ven Marls, Black Ven, Lyme Regis, Dorset, part of England’s iconic Jurassic Coast. The fossil shown in the photographs is the exact specimen you will receive, carefully selected for its preservation, clarity, and scientific value. Full sizing information is provided within the photographs for accurate reference.

All of our fossils are 100% genuine specimens and each is supplied with a Certificate of Authenticity, ensuring confidence for collectors, educators, and enthusiasts.

Geological Formation and Age

This specimen 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 marine mudstones and marls deposited in a shallow epicontinental sea that once covered southern Britain. This formation is internationally significant due to its fossil richness and its importance in defining Early Jurassic stratigraphy. Black Ven is particularly famous for its continuous exposure and abundance of ammonites, making fossils from this locality both scientifically reliable and historically important.

Fossil Type, Species, and Classification

Promicroceras is a classic Early Jurassic ammonite genus belonging to the Order Ammonitida, Superfamily Eoderoceratoidea, and Family Echioceratidae. It is a well-known index fossil, widely used in biostratigraphy to identify and correlate Lower Lias marine sediments. Promicroceras is characteristic of the Promicroceras biozone, a key stratigraphic interval within the Sinemurian, making specimens from this genus especially desirable for collectors with an interest in geological dating and palaeontology.

Morphology and Notable Features

This ammonite displays the typical evolute shell coiling of Promicroceras, with earlier whorls clearly visible and a relatively wide umbilicus. The shell is ornamented with strong, evenly spaced ribbing, often gently curved and occasionally bifurcating across the flanks, giving the fossil a bold and recognisable appearance. The specimen has undergone natural calcite mineralisation, enhancing durability while preserving fine morphological detail. This calcite preservation highlights the original shell form and adds visual contrast, making the fossil particularly 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 seabed, allowing ammonite shells to be rapidly buried after death. Periodic low-oxygen conditions reduced scavenging and bioturbation, contributing to the excellent preservation of ammonites within the Black Ven Marls. These depositional conditions are key to the exceptional fossil record of the Jurassic Coast.

Collecting and Display Value

This Promicroceras calcite ammonite fossil is well suited for private collections, educational use, museum displays, or refined interior presentation. Its classic British provenance, well-defined stratigraphic position, and attractive preservation make it both scientifically meaningful and visually engaging. Each specimen we offer is individually chosen, ensuring you receive a carefully curated and authentic piece of Early Jurassic marine history from one of the world’s most celebrated fossil localities.