RARE Rasenia (Eurasenia) Fossil Ammonite – Lower Kimmeridgian Jurassic – Osmington Mills Dorset UK – Alice Purnell Collection

Description

Offered here is a RARE and well-preserved ammonite fossil, belonging to the genus Rasenia (Eurasenia), from the Lower Kimmeridgian stage of the Late Jurassic Period (~155 million years ago). This remarkable specimen originates from the fossil-rich coastal cliffs of Osmington Mills, Dorset, a location renowned for its beautifully preserved Kimmeridgian fauna.

This piece is part of the celebrated Alice Purnell Collection, which is highly respected for its expertly curated and historically significant UK fossil specimens. The ammonite featured in this listing is the exact one you will receive and is accompanied by a Certificate of Authenticity, guaranteeing the fossil’s identity, age, and provenance.

Scale Rule Squares / Cube = 1cm – Please refer to the listing photo for full sizing and measurements.

Geological & Palaeontological Details:

• Genus: Rasenia
• Subgenus: (Eurasenia)
• Geological Period: Late Jurassic
• Stage: Lower Kimmeridgian
• Formation: Kimmeridge Clay Formation
• Location: Osmington Mills, Dorset, United Kingdom
• Depositional Environment: Low-energy, offshore marine environment with fine clays, indicating deeper water sedimentation
• Biozone: Commonly found within the Baylei Zone, although exact zonal placement can vary
• Fossil Type: Extinct marine ammonite – nektonic, fast-swimming mollusc

Morphological Features:

• Involute shell with compressed whorls
• Characteristic ribbing and occasional tuberculation
• Rounded or slightly keeled venter
• Often shows strong sculpture adapted to its nektonic lifestyle
• This example displays excellent ribbing and definition across the whorls

Taxonomic Classification:

• Family: Aulacostephanidae
• Superfamily: Perisphinctoidea
• Order: Ammonitida
• Class: Cephalopoda
• Phylum: Mollusca

Notable Points:

• Fossils from Osmington Mills are highly sought after due to their clarity and completeness
• The genus Rasenia is used in biostratigraphic correlation across Europe
• Eurasenia is a recognized subgenus with distinctive morphological characteristics
• Excellent specimen for both display and scientific purposes
• From a respected private collection: Alice Purnell Collection

Summary:

This Rasenia (Eurasenia) ammonite fossil is a scientifically significant and visually impressive relic from the Jurassic seas of Dorset. With its clear morphology and rich geological context, it is a superb addition for fossil collectors, educators, and enthusiasts of Earth’s prehistoric life.

Important Notes:

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.

The specimen pictured is the exact one you will receive.

Scale cubes = 1cm. See photo for full dimensions.