RARE 12″ Lewesiceras mantelii Fossil Chalk Ammonite | Turonian Cretaceous | Steyning Bowl Pit Sussex UK | Alice Purnell Collection

Description

This listing presents an EXCEPTIONALLY RARE 12-inch fossil ammonite, Lewesiceras mantelii, from the Turonian Stage of the Cretaceous Period. Discovered in the classic fossil locality of Steyning Bowl Pit, Sussex, United Kingdom, this impressive specimen originates from the esteemed Alice Purnell Collection, renowned for its scientifically curated and display-grade fossils.

Geological Details:

• Locality: Steyning Bowl Pit, Sussex, United Kingdom
• Geological Period: Cretaceous
• Geological Stage: Turonian (~93.9 to 89.8 million years ago)
• Depositional Environment: Open marine chalk sea; low-energy carbonate shelf with abundant planktonic deposition
• Formation: Upper Chalk or equivalent Turonian chalk units of southern England

Paleontological Context: Lewesiceras mantelii is a large and robust ammonite belonging to the Pachydiscidae Family. Its global presence and size make it one of the most iconic ammonites of the Turonian, commonly used in biostratigraphy and as a reference taxon for correlating Turonian strata across Europe and beyond.

• Order: Ammonitida
• Superfamily: Desmoceratoidea
• Family: Pachydiscidae
• Genus: Lewesiceras
• Species: mantelii
• Biozone: Typically associated with the Lewesiceras peramplum Zone, part of the Middle to Upper Turonian ammonite succession
• Formally Described by: J. Sowerby, 1817

Morphological Features:

• Massive, involute shell reaching ~12 inches in diameter
• Strong ribbing and broad, rounded whorls
• Deep umbilicus and thick shell cross-section
• Preserved in light grey to cream chalk matrix typical of British chalk deposits

Notable Characteristics:

• Museum-grade specimen with outstanding size and shell preservation
• Extremely rare UK find from a restricted and historically important fossil locality
• Sourced from the high-quality Alice Purnell Collection, ensuring authenticity and provenance

Authenticity & Presentation:

• 100% genuine fossil, not a replica or reconstruction
• Includes an official Certificate of Authenticity
• The photo shows the exact specimen you will receive
• Scale cube = 1cm for accurate sizing reference (see image)

Additional Notes: This remarkable Lewesiceras mantelii fossil is a true collector’s prize — combining visual grandeur, scientific relevance, and exceptional preservation. Whether you’re a private collector, educator, or institution, this ammonite is a signature piece worthy of display in any major fossil collection.

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