Kosmoceras jasoni Ammonite Fossil | Upper Callovian, Jurassic | Ashton Keynes UK | Alice Purnell Collection | Genuine with Certificate

Description

Fossil Type & Species:

This listing features a genuine ammonite fossil of Kosmoceras jasoni, a distinctive species from the Upper Callovian Stage of the Jurassic Period. This beautifully preserved specimen was discovered in Ashton Keynes, Wiltshire, United Kingdom, and originates from the prestigious Alice Purnell Collection, known for high-quality, well-documented British fossils.

Geological Formation & Insight:

Kosmoceras is a genus within the Kosmoceratidae family, well recognised for its thick, evolute shells with prominent ribbing and tubercles. These ammonites were nektonic marine cephalopods, meaning they were active swimmers and played a major role in the Jurassic marine food chain.

This specimen is from the Upper Callovian Stage of the Middle to Late Jurassic, dated to approximately 164 to 161 million years ago. The marine sediments around Ashton Keynes in Wiltshire are part of the Oxford Clay Formation, one of the UK’s most important and productive Jurassic fossil-bearing units.

The Oxford Clay was deposited in a calm, shallow epicontinental sea that once covered much of southern England. Fossils from this region are renowned for their exceptional preservation, particularly ammonites, marine reptiles, bivalves, and belemnites.

Item Specifics:

• Fossil Type: Ammonite
• Species: Kosmoceras jasoni
• Geological Age: Upper Callovian, Middle/Late Jurassic (~164–161 million years ago)
• Formation: Oxford Clay Formation
• Locality: Ashton Keynes, Wiltshire, United Kingdom
• Provenance: From the Alice Purnell Collection
• Preservation: Excellent detail, showing shell structure and ribbing
• Colour: Natural matrix tones, typically grey or brown
• Size: Please refer to photo – scale rule/cube = 1cm
• Condition: 100% natural specimen with no restoration
• Specimen: You will receive the exact fossil shown in the photograph

Authenticity Guarantee:

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity. This ammonite is from the trusted Alice Purnell Collection, ensuring its scientific value and authentic British provenance.

Shipping & Packaging:

Your fossil will be professionally packed and shipped with tracking. A superb specimen for fossil collectors, educational use, or as a distinctive natural history gift.

Thank you for exploring our shop — be sure to browse more rare and authentic fossils, minerals, and crystals in our full collection!