Tropidoceras Golden Pyrite Ammonite Fossil Jurassic Dorset UK Black Ven Marls Lower Lias Stonebarrow Cliff Charmouth Lyme Regis

Description

Genuine Golden Pyrite Tropidoceras Ammonite from the Jurassic Coast

Presented here is an exceptional Tropidoceras golden pyrite ammonite fossil, collected from the iconic Black Ven Marls at Stonebarrow Cliff, Charmouth, within the world-famous Jurassic Coast at Lyme Regis, Dorset, UK. This is a carefully chosen natural specimen, and the photographs show the exact fossil you will receive, with full sizing clearly visible in the images provided.

This fossil includes a lifetime Certificate of Authenticity on a generic card, confirming it as a genuine natural specimen. The ammonite has been professionally cleaned, prepared, and stabilised to enhance its natural detail while preserving its original geological integrity.

Fossil Type and Species – Tropidoceras

Tropidoceras is a distinctive ammonite genus from the Lower Jurassic (Lower Lias), belonging to the Order Ammonitida, Superfamily Eoderoceratoidea, and Family Eoderoceratidae. These ammonites lived during the Sinemurian Stage, approximately 195 million years ago, when warm, shallow epicontinental seas covered much of southern Britain.

Tropidoceras is particularly significant in Early Jurassic ammonite successions and is commonly associated with well-defined ammonite biozones used in stratigraphic correlation. Dorset specimens are highly valued due to the long history of scientific study and the consistent quality of preservation from the Black Ven Marls.

Morphology and Diagnostic Characteristics

This specimen displays the classic features that define Tropidoceras, including:

• A moderately compressed, evolute shell, with earlier whorls visible
• A strong, continuous ventral keel, a key diagnostic trait
• Well-developed radial ribbing across the flanks
• Clear growth lines reflecting natural shell development and symmetry

The pronounced keel and streamlined shell form suggest Tropidoceras was an active swimmer, adapted for efficient movement through Jurassic marine environments. These features make it a visually striking ammonite and a favourite among collectors.

Golden Pyrite Preservation

One of the most desirable aspects of this fossil is its natural golden pyrite mineralisation. Pyrite formed when iron and sulphur combined under low-oxygen conditions within the fine marine sediments of the Jurassic seabed. Over millions of years, this process replaced or infilled the original shell material, preserving fine surface detail while producing a metallic gold appearance.

Golden pyrite ammonites from the Black Ven Marls are especially sought after because they combine high scientific value with outstanding aesthetic appeal. The reflective pyrite highlights the keel and ribbing, making this specimen particularly impressive under display lighting.

Geological Context – Black Ven Marls, Lower Lias

The Black Ven Marls are part of the Lower Lias sequence and were deposited in a quiet offshore marine environment during the Early Jurassic. Fine-grained muds accumulated on the sea floor, allowing ammonites and other marine organisms to be rapidly buried and fossilised under conditions favourable for mineral replacement.

Stonebarrow Cliff and Charmouth lie within the UNESCO World Heritage-listed Jurassic Coast, one of the most important fossil regions in the world. Fossils from this locality have been collected and studied for over two centuries and remain central to understanding Jurassic marine ecosystems, sedimentology, and ammonite evolution.

Collector, Educational, and Display Value

Tropidoceras ammonites are highly desirable for:

• Fossil and ammonite collectors
• Mineral collectors drawn to pyrite preservation
• Educational and teaching collections
• Display cabinets and curated fossil shelves

The combination of elegant shell form, prominent keel, and golden pyrite mineralisation makes this specimen both visually impressive and scientifically meaningful.

Authenticity and Provenance

• Fossil type: Tropidoceras ammonite
• Preservation: natural golden pyrite
• Formation: Black Ven Marls, Lower Lias
• Geological age: Lower Jurassic, Sinemurian Stage
• Locality: Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK
• Certificate: Lifetime Certificate of Authenticity included

This fossil represents a genuine piece of Dorset’s Jurassic seabed, preserving a marine animal that lived nearly 200 million years ago, and offers a rare opportunity to own a beautifully preserved golden pyrite ammonite from one of the most celebrated fossil localities in the world.