Promicroceras Golden Pyrite Ammonite Fossil Black Ven Marls Lower Lias Jurassic Coast Lyme Regis Dorset UK

Description

Promicroceras – A Golden Pyrite Ammonite from the Jurassic Coast

This stunning specimen is a genuine Promicroceras ammonite fossil, beautifully preserved in golden pyrite from the Black Ven Marls of the Lower Lias Formation, collected at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK. Dating back to the Lower Jurassic (approximately 199–190 million years ago), this ammonite showcases the extraordinary preservation conditions of the Jurassic Coast, where delicate shell structures were replaced by dazzling pyrite crystals.

Discovered on 22 September 2025 by our team members Alister and Alison, the fossil was cleaned, prepped, and treated by Alison with expert care. The result is a specimen that perfectly highlights the ribbed morphology and elegant coiling of Promicroceras, while gleaming with natural golden brilliance. Every piece is guaranteed genuine and comes with a Certificate of Authenticity.

Geological Setting – Black Ven Marls and Stonebarrow Cliff

The Black Ven Marls, part of the Lower Lias, are world-renowned for their rich fossil deposits, stretching along the Jurassic Coast UNESCO World Heritage Site. This formation is composed of alternating shales and mudstones, laid down in a shallow marine environment where low oxygen levels aided exceptional fossil preservation.

Stonebarrow Cliff, near Charmouth and Lyme Regis, is one of the most productive fossil localities in Britain. Generations of collectors have explored this stretch of coastline, made famous by early paleontologists such as Mary Anning. Ammonites from this region, especially those preserved in pyrite, are considered among the finest in the world for their aesthetic beauty and scientific value.

Species Profile – Promicroceras

Promicroceras is a small, tightly coiled ammonite belonging to the order Ammonitida, within the subclass Ammonoidea. It is a characteristic genus of the Sinemurian stage of the Lower Jurassic. Promicroceras is easily identified by its ribbed shell, narrow whorls, and distinctive suture lines.

These ammonites were active swimmers (nektonic carnivores), preying on plankton and small marine creatures. Their shells, with chambered interiors, functioned as buoyancy devices, enabling efficient movement in the open ocean. For paleontologists, Promicroceras is an important index fossil, helping to date Sinemurian-aged rock strata with precision.

Collectible and Scientific Importance

Promicroceras ammonites are prized by collectors for both their scientific role and their remarkable beauty. When preserved in golden pyrite, they take on a striking metallic luster, making them ideal as display fossils. The combination of golden colour, fine ribbing, and historic locality at Lyme Regis ensures that each specimen is unique and highly desirable.

Fossil Details

• Genus: Promicroceras
• Type: Golden Pyrite Ammonite Fossil
• Geological Formation: Black Ven Marls, Lower Lias
• Age: Lower Jurassic, Sinemurian (~199–190 million years ago)
• Location: Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK
• Discovered by: Alister and Alison
• Discovery Date: 22 September 2025
• Prepared by: Alison
• Guarantee: 100% genuine specimen with Certificate of Authenticity

The photographs show the exact specimen you will receive, with a 1 cm scale cube for accurate sizing. This Promicroceras golden pyrite ammonite is a perfect combination of natural history, scientific value, and aesthetic appeal, making it an outstanding addition to any fossil collection or display.