Ammonite - Fossilised shell - Promicroceras (Charmouth) - 19 mm - 74 mm (No Reserve Price)

This rare Promicroceras ammonite comes from the internationally famous Jurassic Coast of Dorset, a UNESCO World Heritage Site recognised for its outstanding geological history. Sourced from Stonebarrow Cliff, Charmouth, within the fossil-rich Black Ven Marls of the Lower Lias, this specimen dates to the Sinemurian Stage of the Early Jurassic period. The fossil offered here is the exact piece shown in the photographs, carefully selected for its scientific value, clarity of detail, and excellent display quality. Each of our fossils is 100% genuine and includes a Certificate of Authenticity.

Geological Setting and Formation

The Black Ven Marls form part of a well-known Lower Jurassic sequence deposited around 195 million years ago. These dark shales and marls accumulated in a calm marine environment where fine sediments settled gently onto the seafloor. The exceptional preservation of ammonites from this area is due to the low-oxygen conditions that limited decay. Over millions of years, the layers lithified into rock, encapsulating specimens like Promicroceras in remarkable detail. Stonebarrow Cliff remains one of the most productive fossil localities along the Jurassic Coast, continually revealing new material through natural erosion.

Taxonomy and Scientific Importance

Promicroceras belongs to the family Oxynoticeratidae within the order Ammonitida, a diverse and scientifically important group of extinct cephalopods. It is one of the most recognisable genera of the Sinemurian and plays a significant role in early Jurassic biostratigraphy. Promicroceras ammonites are key index fossils for correlating Sinemurian-age rock layers across Europe, helping palaeontologists build accurate timelines of geological development. Their abundance and distinctive morphology make them central to understanding ammonite evolution during the early stages of the Jurassic seas.

Morphology and Notable Features

This specimen exhibits the classic Promicroceras shell form: a small, tightly coiled discoidal shell with fine, evenly spaced ribs. These ribs run cleanly across the whorls, creating a delicate yet well-defined texture. The venter is narrow and smooth, contributing to the characteristic symmetry of the genus. Preservation quality is excellent, allowing the subtle suture lines and growth patterns to be observed clearly. Specimens from the Black Ven Marls often display a pleasing mineral sheen due to calcite infill, enhancing both scientific study and aesthetic appeal.

Depositional Environment

During the Sinemurian Stage, the region that is now Dorset lay below a shallow epicontinental sea teeming with marine life. Conditions on the seafloor were stable and largely undisturbed, with fine muds steadily accumulating. These sediments provided protective burial for ammonite shells shortly after they reached the sea bottom. Over time, mineral-rich waters percolated through the marls, improving fossil preservation and creating the distinctive calcite replacement often seen in Promicroceras specimens. This environment has yielded one of the most detailed and continuous early Jurassic fossil records in the world.

Provenance and Collector Appeal

This Promicroceras ammonite originates from Stonebarrow Cliff, a location renowned for producing some of the finest Lower Lias ammonites available to collectors. Its combination of scientific importance, excellent preservation, and aesthetic charm makes it a standout addition to any fossil collection. Whether for display, research, or educational use, this carefully selected specimen embodies the exceptional geological heritage of the Jurassic Coast and represents a fascinating piece of natural history.

Weight: 108g
Size of ammonite:: 20 x 18mm
Size of matrix: 74 x 60 x 19mm

Prepped and found by our own Team

Shipped by Royal Mail Fully Tracked