Description
Authentic Jurassic Coast Promicroceras Ammonite Fossil
This is a genuine “popped” Promicroceras ammonite fossil collected from the famous Black Ven Marls of the Lower Lias on the Jurassic Coast at Lyme Regis, Dorset, UK. Charmouth and Lyme Regis are world-renowned for producing exceptionally preserved Lower Jurassic fossils, and this specimen is a fine example of the classic small ammonites that define this historic coastline. The fossil you see in the photographs is the exact specimen you will receive, carefully selected for quality and display appeal. It includes a Certificate of Authenticity lifetime guarantee card, confirming its genuine natural origin.
Geological Age and Formation
This fossil originates from the Lower Jurassic period, approximately 199–190 million years ago, specifically within the Lower Lias sequence. The Black Ven Marls are part of a succession of marine sediments laid down in a shallow epicontinental sea that once covered much of southern Britain. These fine-grained marls and shales are particularly well known for preserving delicate fossils, including ammonites, belemnites, and marine reptiles. The depositional environment was a low-energy marine setting, allowing organisms like ammonites to settle gently on the seabed and be rapidly buried, aiding their preservation.
Fossil Type and Species Details
Promicroceras is a genus of small ammonites belonging to the order Ammonitida, within the subclass Ammonoidea. These cephalopods are extinct relatives of modern squid and octopus, possessing tightly coiled, ribbed shells. Promicroceras is especially characteristic of the Lower Sinemurian stage of the Early Jurassic and is widely used as an index fossil for biostratigraphy, helping geologists date rock layers with precision.
The “popped” nature of this specimen refers to the natural splitting of the rock along the fossil, revealing the ammonite in relief. This creates a striking visual effect, often exposing fine ribbing and whorl structure. The shell typically displays strong, evenly spaced ribs radiating across the whorls, a key morphological feature of the genus.
Morphology and Preservation
This specimen shows the classic planispiral coiling typical of ammonites, with visible ribbing that enhances both scientific and aesthetic value. The preservation within the marl matrix highlights the natural contrast between fossil and host rock, making it an excellent display piece. The fossil has been naturally revealed through splitting rather than artificial preparation, maintaining its authenticity and geological context.
Location Significance – Black Ven, Lyme Regis
Black Ven is one of the most productive fossil sites along the Jurassic Coast, a UNESCO World Heritage Site. Continuous coastal erosion exposes new fossils regularly, making it a prime location for collectors and researchers alike. Fossils from this locality are highly desirable due to their provenance and historical significance, with Lyme Regis famously associated with pioneering fossil hunter Mary Anning.
Display, Collection, and Investment Value
This Promicroceras ammonite is ideal for collectors of British fossils, Jurassic specimens, or ammonites in general. Its clear structure, authentic provenance, and classic locality make it suitable for display, educational use, or as part of a growing geological collection. Each piece from this region carries both scientific importance and timeless natural beauty.
Authenticity and Guarantee
This fossil is 100% genuine and not a replica. It comes complete with a Certificate of Authenticity lifetime guarantee card. The specimen has been carefully chosen, and the photographs accurately represent the exact fossil you will receive. For full dimensions, please refer to the provided images.






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