Multi Promicroceras Ammonite Cluster Fossil Jurassic Coast Dorset UK

Description

Multi-Cluster of Promicroceras Ammonite Fossils – Jurassic Coast, Dorset, UK

This superb natural cluster of Promicroceras ammonite fossils comes from the world-famous Black Ven Marls, Lower Lias, on the Jurassic Coast at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK. This region is globally renowned for its Early Jurassic fossil record and is one of the richest ammonite-bearing localities in Europe.

Your exact specimen was discovered by our team members, Alister and Alison, on 25 November 2025, and has been professionally cleaned, prepared, and treated by Alison. The photographs show the actual fossil you will receive, with a 1 cm scale cube included to provide accurate sizing.

All of our fossils are 100% genuine specimens and are supplied with a Certificate of Authenticity.

Geological Background – Lower Lias, Early Jurassic

The ammonites in this cluster were preserved in the Lower Lias, an Early Jurassic geological sequence dating back approximately 199–190 million years. The Black Ven Marls form part of the Charmouth Mudstone Formation, a sedimentary unit laid down in a quiet, offshore marine setting.

During this time, Dorset lay beneath warm tropical seas where fine muds accumulated slowly on the seafloor. These low-oxygen sediments provided ideal conditions for fossil preservation. The ammonites within this deposit are often found in exceptional detail, with complete ribbing, tight coiling, and crisp ornamentation characteristic of Promicroceras.

The Lower Lias is an important biostratigraphic interval in palaeontology, widely used to correlate marine rock layers across Europe due to its abundant and well-defined ammonite fauna.

Promicroceras – Iconic Lower Jurassic Ammonite

Promicroceras is one of the most recognisable ammonites from the Early Jurassic and is particularly associated with the Charmouth and Lyme Regis coastlines. These ammonites belong to the order Ammonitida, within the superfamily Psiloceratoidea, and are noted for their distinctive small size and elegant, tightly coiled shells.

Key identifying features include:

• Fine, evenly spaced ribbing that continues across the shell
• Tight, rounded whorls forming a compact spiral
• Consistent morphology, making them excellent index fossils
• High preservational detail when found in Black Ven Marls

Collecting clusters is especially desirable, as they represent natural associations created during deposition, offering insight into ammonite communities rather than isolated individuals.

Depositional Environment & Scientific Interest

The Black Ven Marls represent a low-energy marine basin where sedimentation occurred at a steady rate. Ammonites, once deceased, settled gently on the seafloor and were rapidly buried by fine muds. This environment minimised scavenging and physical disturbance, allowing for the preservation of numerous tightly packed ammonites on a single bedding plane.

Such clusters provide valuable information about Early Jurassic biodiversity, population density, and the ecological interactions of ammonites in ancient marine ecosystems. They are also prized display pieces for collectors because they present multiple well-preserved fossils in a natural, aesthetically balanced matrix.

Authenticity, Preparation & Presentation

• 100% genuine fossil specimen

• Certificate of Authenticity included

• Professionally prepared by Alison for optimum preservation

• Discovered in situ by our own team members

• Exact specimen shown in the photographs is the one you will receive

• Scale cube = 1 cm to assist with accurate sizing

This natural Promicroceras cluster is a scientifically meaningful and visually impressive fossil from the UNESCO-designated Jurassic Coast, making it an ideal addition to any collection.