Description
Genuine Promicroceras Golden Pyrite Ammonite Fossil Bed from the Jurassic Coast
This specimen is a striking Promicroceras Golden Pyrite ammonite fossil bed preserved in a multiblock formation from the world-famous Jurassic Coast, UK. Sourced from the Black Ven Marls of the Lower Lias, this remarkable piece was discovered at Black Ven, Lyme Regis, Dorset, one of the most iconic fossil locations in the world. The fossil you see in the photos is the exact specimen you will receive, with a scale cube of 1 cm included for accurate sizing reference.
The specimen was discovered on 23 September 2025 by our own team members, Alister and Alison, and has been meticulously cleaned, prepped, and treated by Alison to ensure that both its scientific detail and natural beauty are preserved. Every purchase comes complete with a Certificate of Authenticity, giving you peace of mind that this is a 100% genuine fossil.
Geological Age and Locality
The Black Ven Marls of Lyme Regis are part of the Lower Lias sequence of the Lower Jurassic, approximately 199–196 million years old. This deposit forms part of the Charmouth Mudstone Formation, which has long been celebrated for producing exceptionally preserved ammonites, belemnites, and marine reptiles. The locality lies within the UNESCO World Heritage-listed Jurassic Coast, known worldwide for its palaeontological importance and its role in the history of geology.
This multiblock specimen captures the fossil-rich environment of the Lower Jurassic seabed, where countless ammonites were buried and mineralised. Over millions of years, iron pyrite replaced the original aragonite shell structure, producing the golden metallic sheen that makes these ammonites so visually stunning.
Species Information – Promicroceras
Promicroceras belongs to the order Ammonitida, within the superfamily Psiloceratoidea and family Eoderoceratidae. It is a small but distinctive ammonite, typically with finely ribbed, tightly coiled shells. The ribs are evenly spaced and extend across the whorls, giving the fossil a characteristic textured appearance.
The genus is particularly associated with the Lower Lias and is a key indicator species within the early Jurassic biostratigraphy. Fossils of Promicroceras are often used by geologists to identify specific biozones, notably within the Sinemurian stage. The small size, ribbed morphology, and pyritised preservation make these ammonites highly prized both scientifically and aesthetically.
Formation and Preservation
The golden appearance of these ammonites is due to natural pyritisation, where iron sulphides within the marine sediments replaced the shell material during fossilisation. This unique process preserves exquisite detail, including ribbing and suture lines, while giving the ammonite a gleaming, metallic surface.
The multiblock structure of this specimen reveals a natural cluster of Promicroceras ammonites preserved together, providing a snapshot of life and death in the Lower Jurassic seas. These fossil beds offer insight into the ecological conditions of the time and showcase the density of ammonite populations that once thrived in these ancient waters.
Collector and Display Value
Fossils from Lyme Regis have fascinated collectors and scientists alike for centuries, dating back to the pioneering discoveries of Mary Anning in the early 19th century. Today, specimens like this Promicroceras fossil bed remain some of the most desirable ammonites available due to their rarity, locality, and stunning pyrite preservation.
This particular fossil is ideal for display, with its multiblock arrangement adding depth and visual interest. It holds equal appeal for serious fossil collectors, amateur enthusiasts, educators, and those looking for a unique natural history gift. The combination of geological history, natural artistry, and golden sheen ensures that it will stand out as a centrepiece in any collection.
All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.
Reviews
There are no reviews yet.