Description
Overview & Authenticity
This listing features a genuine Promicroceras calcite ammonite fossil, collected from the renowned Black Ven Marls along the Jurassic Coast at Black Ven, Lyme Regis, Dorset, UK. This specimen has been carefully selected for its preservation quality and natural visual appeal. The photographs show an example of the actual fossil you will receive, ensuring complete transparency when purchasing.
The fossil is supplied with a Certificate of Authenticity, including a lifetime guarantee of genuineness, provided on a generic authenticity card, making it a secure and trustworthy addition to any collection.
Geological Setting
The fossil originates from the Lower Lias Group, dating to the Early Jurassic Period, approximately 195–190 million years ago. During this time, the area that is now Dorset was submerged beneath a shallow, warm marine environment. Fine-grained marls and mudstones accumulated on the seafloor, creating ideal conditions for fossil preservation.
Black Ven is one of the most famous fossil localities in the world, known for its continuous erosion and frequent exposure of new material. Fossils from this site have played a major role in the historical development of palaeontology and continue to be of international scientific importance.
Fossil Type & Classification
This specimen is an ammonite, an extinct marine cephalopod closely related to modern squid, octopus, and cuttlefish.
- Order: Ammonitida
- Superfamily: Psiloceratoidea
- Family: Psiloceratidae
- Genus: Promicroceras
Promicroceras is an important early Jurassic ammonite genus, commonly used as an index fossil for the earliest part of the Jurassic. Its presence helps define key biozones within the Lower Lias and marks the rapid diversification of ammonites following the end-Triassic mass extinction.
Morphology & Preservation
Promicroceras ammonites are typically small, planispirally coiled shells with gently rounded whorls. Ribbing is fine and regular, sweeping forward across the shell flanks and becoming more defined toward the outer whorl. This specimen displays attractive natural calcite mineralisation, which enhances the shell structure and provides contrast against the darker marl matrix.
The fossil retains clear three-dimensional form, allowing both the coiling pattern and surface ornamentation to be easily observed, making it suitable for study as well as display.
Depositional Environment & Palaeoecology
During the Early Jurassic, ammonites like Promicroceras inhabited the open water column, where they were active swimmers and predators. After death, their shells settled onto the soft seabed. Low-energy conditions, combined with rapid burial in fine sediment, limited disturbance and promoted fossilisation. Over geological time, mineral-rich fluids replaced shell material with calcite, resulting in the preservation seen today.
Collectability & Display Appeal
Ammonites from Lyme Regis and Black Ven are highly sought after due to their classic British Jurassic provenance and scientific relevance. This Promicroceras calcite ammonite is ideal for fossil collectors, educational collections, interior display, or as a meaningful geological gift.
Full sizing details are provided in the photographs. As a carefully chosen, authentic specimen from one of the world’s most famous fossil localities, this fossil represents both deep geological time and the rich natural history of the Jurassic Coast.
