Promicroceras Calcite Ammonite Fossil Pebble Jurassic Coast Black Ven Charmouth Dorset UK

Description

Specimen Overview

Offered here is a genuine Promicroceras calcite ammonite fossil pebble collected from the famous Black Ven Marls at Charmouth, near Lyme Regis, Dorset. This carefully selected specimen combines a naturally rounded pebble form with a clearly visible ammonite preserved in calcite, creating an attractive and tactile fossil that is both display-friendly and geologically authentic. The ammonite remains firmly embedded within its original matrix, with the pebble shape formed entirely through natural coastal processes rather than artificial polishing. The photographs show the exact specimen you will receive, and full sizing details are clearly visible. As with all of our fossils, this piece is 100% genuine and supplied with a Certificate of Authenticity.

Geological Formation & Provenance

The fossil originates from Black Ven, one of the most important and productive fossil localities on the Jurassic Coast, a UNESCO World Heritage Site internationally recognised for its geological significance. The Black Ven Marls belong to the Lower Lias Group, deposited during the Early Jurassic Period, approximately 199–196 million years ago. These fine-grained marine mudstones were laid down in a relatively calm offshore environment, ideal for preserving ammonite shells. Ongoing coastal erosion at Black Ven naturally releases fossils from the cliffs, and some specimens are gently rounded by wave action into pebble forms while retaining their internal fossil detail.

Fossil Type & Taxonomic Context

Promicroceras is an extinct genus of ammonite belonging to the Class Cephalopoda, Subclass Ammonoidea, and Order Ammonitida. Ammonites were free-swimming marine molluscs related to modern squid and cuttlefish and were among the most abundant and diverse animals in Jurassic seas. Promicroceras is particularly characteristic of early Lower Lias ammonite assemblages and is widely recognised for its stratigraphic importance in Early Jurassic marine successions.

Morphology & Calcite Preservation

This specimen preserves the recognisable coiled shell morphology of Promicroceras, with whorl outlines visible through calcite mineralisation. Calcite replacement has strengthened the fossil and enhanced contrast between the shell and surrounding marl, allowing key features to remain visible despite the naturally smoothed pebble exterior. The pebble form is entirely the result of natural marine and coastal erosion, offering a genuine example of how fossils are shaped and revealed along the Dorset coastline.

Depositional Environment & Natural Formation

During the Early Jurassic, the area now forming Dorset lay beneath a warm, shallow sea rich in marine life. Ammonites such as Promicroceras thrived in these waters, swimming actively in search of prey. After death, shells settled onto the seabed and were buried by fine muds, later compacting into marl. Millions of years later, erosion at Black Ven exposed these fossils, and some were naturally rounded into pebble forms while preserving the ammonite within, creating specimens like this example.

Scientific & Collecting Significance

Ammonites from Black Ven, Charmouth, and Lyme Regis have been collected and studied for over two centuries and played a central role in the development of geological and stratigraphic science. Fossils from Black Ven are internationally recognised for their reliable provenance and scientific credibility. Pebble ammonites are especially appealing to collectors as they combine clear fossil preservation with a naturally finished, handling-friendly form that highlights the dynamic coastal processes of the Jurassic Coast.

Display, Care & Authenticity

This fossil is ideal for display in a private collection, educational setting, or natural history cabinet, and is equally suited to close handling and examination. The specimen has been carefully cleaned to reveal natural features, with no artificial restoration or reconstruction. You will receive the exact fossil shown, accompanied by a Certificate of Authenticity, confirming its origin and genuine nature.

A classic and tactile ammonite from one of Britain’s most iconic fossil cliffs, this Promicroceras calcite ammonite fossil pebble from the Black Ven Marls represents an authentic piece of Early Jurassic marine history from the Jurassic Coast, Dorset, UK.