Fossils for Sale - High-quality BRITISH and WORLDWIDE Fossils. An impressive selection of fossils, including Ammonites, Trilobites, Belemnites, Fossil Fish, Fossil Shark Teeth, Fossilised Insects in Amber, Dinosaurs, and Reptiles. UK Fossils was formed in 1988 and collects and preps our own fossils in the heart of the Jurassic Coast, collecting fossils from Lyme Regis, Charmouth and Somerset. Our passion for fossils is reflected in our carefully curated collection, which includes some of the rarest and most unique specimens available.

FREE UK DELIVERY - Save up to 60%

Arnioceras Fossil Ammonite Jurassic Coast Lyme Regis Dorset UK – Genuine Black Ven Marls Lower Lias Specimen with COA
Arnioceras Fossil Ammonite Jurassic Coast Lyme Regis Dorset UK – Genuine Black Ven Marls Lower Lias Specimen with COA - Image 2

Arnioceras Fossil Ammonite Jurassic Coast Lyme Regis Dorset UK – Genuine Black Ven Marls Lower Lias Specimen with COA

£24.00

Authentic Arnioceras Fossil Ammonite from the Jurassic Coast, Dorset

This exceptional Arnioceras Fossil Ammonite was discovered within the famous Black Ven Marls of the Lower Lias Formation, part of the Jurassic Coast at Black Ven, Lyme Regis, Dorset, UK. Unearthed by our experienced fossil collectors Alister and Alison on 05 November 2025, this specimen has been expertly cleaned, prepped, and treated by Alison to museum-grade standards. Dating from the Early Jurassic (Sinemurian) Stage, around 195–200 million years ago, it represents a beautifully preserved example of one of the earliest ammonite lineages from Britain’s world-renowned Jurassic Coast.

Geological and Scientific Context

The genus Arnioceras is a member of the family Arietitidae, within the superfamily Psiloceratoidea and the order Ammonitida, a group of extinct marine cephalopods related to modern-day squid and cuttlefish. These ammonites thrived in the Sinemurian Stage of the Early Jurassic and are used by geologists to define the Arnioceras semicostatum Biozone, an important stratigraphic zone marking one of the earliest divisions of the Lower Lias sequence. The presence of Arnioceras fossils helps scientists identify and correlate layers of Jurassic rock across Europe, making this genus significant in both palaeontology and stratigraphy.

The Black Ven Marls, part of the Charmouth Mudstone Formation, are celebrated worldwide for their exceptional fossil preservation. Deposited in a low-energy, shallow marine environment, these fine-grained marls and clays accumulated in calm waters with low oxygen levels, ideal for fossilisation. Over millions of years, mineral-rich sediments preserved the intricate details of organisms like Arnioceras, allowing modern collectors to admire them in extraordinary condition.

Morphology and Distinctive Features

The Arnioceras ammonite is characterised by its evolute shell, where all whorls are visible from above. The shell displays prominent radial ribs that sweep boldly across each whorl, giving it a distinctive, sculpted texture. These ribs terminate sharply at the venter (outer edge), forming a pronounced keel. The combination of open coiling, deep ribbing, and strong symmetry makes Arnioceras instantly recognisable among ammonites from the Lower Lias.

This specimen exhibits particularly fine preservation, with clear ribbing and natural curvature enhanced by expert preparation. Its form reflects an active, nektonic lifestyle—this ammonite would have swum freely through Jurassic seas, using jet propulsion to navigate and hunt small prey. The well-defined sutures and thick shell construction suggest evolutionary adaptations for both buoyancy and shell strength, enabling survival in deeper or more turbulent waters.

Each rib and whorl of this fossil represents millions of years of Earth’s history, captured within the fine sediments of the Dorset coast. The Arnioceras’ elegant form also makes it a highly desirable piece for display, bridging scientific value with natural beauty.

Geological Age and Depositional Environment

Dating to the Sinemurian Stage of the Lower Jurassic, approximately 197 million years ago, this ammonite was part of an ancient marine ecosystem that existed long before the age of dinosaurs reached its peak. The Black Ven Marls near Lyme Regis are among the most fossiliferous deposits in Britain and form part of the UNESCO World Heritage-listed Jurassic Coast. The alternating layers of marl and limestone were deposited in tranquil, shallow seas, allowing shells and organic material to settle undisturbed and fossilise in perfect detail.

The depositional environment of the Black Ven Marls was marked by periods of low oxygen, resulting in minimal decay and exceptional preservation. As a result, fossils from this locality often retain fine details of shell structure, ribbing, and even mineral infill patterns—making them prized among collectors and researchers alike.

Preparation and Provenance

This specimen was discovered and prepared by our in-house team, ensuring authenticity, provenance, and quality at every stage. Alison’s meticulous preparation reveals the ammonite’s intricate detail while maintaining the fossil’s natural integrity. Gentle mechanical cleaning and consolidation techniques have been used to preserve its structure for long-term stability. Every fossil we offer is 100% genuine and includes a Certificate of Authenticity, verifying its origin, identification, and geological age.

This provenance guarantees that the fossil was ethically collected and responsibly handled, following best practices in preparation and conservation. Its stunning appearance and geological importance make it suitable for collectors, educators, and museums alike.

Size and Presentation

Scale cube = 1 cm. Please refer to the photographs for full sizing details. The images show the exact specimen you will receive—not a stock image. The ammonite is beautifully presented within its natural marl matrix, which enhances its aesthetic appeal and provides geological context. The contrast between the fine-grained matrix and the fossil’s crisp ribbing creates an eye-catching display suitable for both scientific and decorative presentation.

A Collector’s Treasure from the Heart of the Jurassic Coast

This Arnioceras Fossil Ammonite is a remarkable and authentic piece of Dorset’s geological heritage. Combining scientific significance with striking natural beauty, it captures the essence of the Jurassic Coast—a window into ancient seas where ammonites like Arnioceras once thrived. Carefully prepared and guaranteed genuine, it is a true collector’s fossil representing the best of British palaeontology.

(Actual as seen)

Only 1 left in stock

SKU: CF3446 Category:

Description

Authentic Arnioceras Fossil Ammonite from the Jurassic Coast, Dorset

This exceptional Arnioceras Fossil Ammonite was discovered within the famous Black Ven Marls of the Lower Lias Formation, part of the Jurassic Coast at Black Ven, Lyme Regis, Dorset, UK. Unearthed by our experienced fossil collectors Alister and Alison on 05 November 2025, this specimen has been expertly cleaned, prepped, and treated by Alison to museum-grade standards. Dating from the Early Jurassic (Sinemurian) Stage, around 195–200 million years ago, it represents a beautifully preserved example of one of the earliest ammonite lineages from Britain’s world-renowned Jurassic Coast.

Geological and Scientific Context

The genus Arnioceras is a member of the family Arietitidae, within the superfamily Psiloceratoidea and the order Ammonitida, a group of extinct marine cephalopods related to modern-day squid and cuttlefish. These ammonites thrived in the Sinemurian Stage of the Early Jurassic and are used by geologists to define the Arnioceras semicostatum Biozone, an important stratigraphic zone marking one of the earliest divisions of the Lower Lias sequence. The presence of Arnioceras fossils helps scientists identify and correlate layers of Jurassic rock across Europe, making this genus significant in both palaeontology and stratigraphy.

The Black Ven Marls, part of the Charmouth Mudstone Formation, are celebrated worldwide for their exceptional fossil preservation. Deposited in a low-energy, shallow marine environment, these fine-grained marls and clays accumulated in calm waters with low oxygen levels, ideal for fossilisation. Over millions of years, mineral-rich sediments preserved the intricate details of organisms like Arnioceras, allowing modern collectors to admire them in extraordinary condition.

Morphology and Distinctive Features

The Arnioceras ammonite is characterised by its evolute shell, where all whorls are visible from above. The shell displays prominent radial ribs that sweep boldly across each whorl, giving it a distinctive, sculpted texture. These ribs terminate sharply at the venter (outer edge), forming a pronounced keel. The combination of open coiling, deep ribbing, and strong symmetry makes Arnioceras instantly recognisable among ammonites from the Lower Lias.

This specimen exhibits particularly fine preservation, with clear ribbing and natural curvature enhanced by expert preparation. Its form reflects an active, nektonic lifestyle—this ammonite would have swum freely through Jurassic seas, using jet propulsion to navigate and hunt small prey. The well-defined sutures and thick shell construction suggest evolutionary adaptations for both buoyancy and shell strength, enabling survival in deeper or more turbulent waters.

Each rib and whorl of this fossil represents millions of years of Earth’s history, captured within the fine sediments of the Dorset coast. The Arnioceras’ elegant form also makes it a highly desirable piece for display, bridging scientific value with natural beauty.

Geological Age and Depositional Environment

Dating to the Sinemurian Stage of the Lower Jurassic, approximately 197 million years ago, this ammonite was part of an ancient marine ecosystem that existed long before the age of dinosaurs reached its peak. The Black Ven Marls near Lyme Regis are among the most fossiliferous deposits in Britain and form part of the UNESCO World Heritage-listed Jurassic Coast. The alternating layers of marl and limestone were deposited in tranquil, shallow seas, allowing shells and organic material to settle undisturbed and fossilise in perfect detail.

The depositional environment of the Black Ven Marls was marked by periods of low oxygen, resulting in minimal decay and exceptional preservation. As a result, fossils from this locality often retain fine details of shell structure, ribbing, and even mineral infill patterns—making them prized among collectors and researchers alike.

Preparation and Provenance

This specimen was discovered and prepared by our in-house team, ensuring authenticity, provenance, and quality at every stage. Alison’s meticulous preparation reveals the ammonite’s intricate detail while maintaining the fossil’s natural integrity. Gentle mechanical cleaning and consolidation techniques have been used to preserve its structure for long-term stability. Every fossil we offer is 100% genuine and includes a Certificate of Authenticity, verifying its origin, identification, and geological age.

This provenance guarantees that the fossil was ethically collected and responsibly handled, following best practices in preparation and conservation. Its stunning appearance and geological importance make it suitable for collectors, educators, and museums alike.

Size and Presentation

Scale cube = 1 cm. Please refer to the photographs for full sizing details. The images show the exact specimen you will receive—not a stock image. The ammonite is beautifully presented within its natural marl matrix, which enhances its aesthetic appeal and provides geological context. The contrast between the fine-grained matrix and the fossil’s crisp ribbing creates an eye-catching display suitable for both scientific and decorative presentation.

A Collector’s Treasure from the Heart of the Jurassic Coast

This Arnioceras Fossil Ammonite is a remarkable and authentic piece of Dorset’s geological heritage. Combining scientific significance with striking natural beauty, it captures the essence of the Jurassic Coast—a window into ancient seas where ammonites like Arnioceras once thrived. Carefully prepared and guaranteed genuine, it is a true collector’s fossil representing the best of British palaeontology.

Additional information

Era

Jurassic
Origin

United Kingdom

Jurassic Information

The Jurassic Period (201–145 million years ago) was the golden age of dinosaurs, with iconic species like Brachiosaurus, Stegosaurus, and Allosaurus dominating the land. It was a time of warm, humid climates, with high sea levels that created vast shallow seas, supporting abundant marine reptiles, ammonites, and early coral reefs. The first birds, such as Archaeopteryx, evolved from small theropod dinosaurs, while early mammals remained small and nocturnal. Lush forests of cycads, conifers, and ferns covered the land, providing food for giant herbivores. The breakup of the supercontinent Pangaea accelerated, shaping Earth's geography and setting the stage for the diverse ecosystems of the Cretaceous.

Reviews

There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

Related products