Asteroceras Fossil Calcite Ammonite Jurassic Dorset UK Black Ven Marls Lower Lias Stonebarrow Cliff Charmouth Lyme Regis

Description

Genuine Asteroceras Ammonite from the Jurassic Coast

Presented here is an authentic Asteroceras fossil calcite ammonite, collected from the famous Black Ven Marls at Stonebarrow Cliff, Charmouth, part of the world-renowned Jurassic Coast at Lyme Regis, Dorset, UK. This is a carefully selected natural specimen, with photographs showing the exact fossil you will receive. Full sizing and scale can be clearly seen in the images provided.

The fossil was discovered by our own team members, Alister and Alison, on 25 January 2026, and has been professionally cleaned, prepared, and stabilised by Alison to ensure long-term preservation and display quality. Included with the specimen is a lifetime Certificate of Authenticity on a generic card, guaranteeing it as a genuine fossil.

Species Overview – Asteroceras

Asteroceras is a classic and highly recognisable ammonite genus from the Lower Jurassic (Lower Lias), belonging to the Order Ammonitida, Superfamily Psiloceratoidea, and Family Arietitidae. These ammonites lived during the Sinemurian Stage, a time when warm, shallow seas covered much of southern Britain.

Asteroceras is particularly valued by collectors for its bold appearance and its importance in early Jurassic ammonite evolution. Specimens from the Dorset coast are internationally collected due to their historical significance and strong preservation.

Morphology and Calcite Preservation

This specimen displays the characteristic evolute coiling of Asteroceras, with earlier whorls clearly visible. The shell is defined by:

• Strong, evenly spaced radial ribs
• A broad, rounded whorl section
• Clear growth patterning and symmetry

The original aragonite shell has been naturally replaced by calcite, a common and highly desirable mode of preservation within the Black Ven Marls. This mineral replacement enhances surface detail and gives the fossil a striking appearance while remaining entirely natural and unaltered.

Geological Context – Black Ven Marls, Lower Lias

The Black Ven Marls are part of the Lower Lias sequence and were deposited in a shallow marine environment around 195 million years ago. These fine-grained sediments accumulated on a quiet sea floor, creating ideal conditions for the preservation of ammonites and other marine life.

Stonebarrow Cliff and Charmouth are among the most famous fossil localities in the world and form part of the UNESCO-listed Jurassic Coast. Fossils from this area have been studied for over two centuries and continue to play a key role in understanding Jurassic marine ecosystems.

Collector, Educational, and Display Value

Asteroceras ammonites are highly sought after by:

• Fossil and ammonite collectors
• Educational institutions and teaching collections
• Display cabinets and natural history enthusiasts
• Those seeking a genuine British Jurassic fossil

The calcite preservation and clear ribbing make this specimen visually striking, while its manageable size allows for easy display without mounting.

Provenance and Authenticity

• Fossil: Asteroceras calcite ammonite
• Formation: Black Ven Marls, Lower Lias
• Age: Lower Jurassic, Sinemurian
• Locality: Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK
• Discovered: 25 January 2026 by Alister and Alison
• Prepared by: Alison
• Certificate: Lifetime Certificate of Authenticity included

This fossil represents a genuine piece of Dorset’s Jurassic heritage, preserving a marine animal that lived nearly 200 million years ago in the ancient seas that once covered southern England.