Rare Calycoceras inerme Fossil Ammonite Middle Cenomanian Cretaceous Sussex UK – Genuine Collector Specimen with Certificate of Authenticity

Description

Rare Calycoceras inerme Fossil Ammonite from Sussex, UK

This exceptional Calycoceras inerme fossil ammonite is a rare and scientifically significant specimen from the Middle Cenomanian stage of the Late Cretaceous Period. Collected from the renowned chalk deposits of Sussex, United Kingdom, it represents a classic example of one of the most recognisable ammonite genera from this geological interval. The exact specimen shown in the photographs is the one you will receive, carefully selected for its preservation, authenticity, and display appeal.

Geological Age and Provenance

Calycoceras inerme lived approximately 98–95 million years ago, during the Middle Cenomanian. This was a time when southern England was covered by a warm, shallow sea connected to the Tethys Ocean. The soft chalk beds of Sussex were formed from the slow accumulation of microscopic calcareous plankton known as coccolithophores, creating the perfect environment for the preservation of marine life.

The Cenomanian stage is the first of the Late Cretaceous and is marked by a high diversity of ammonites, many of which are used as key index fossils for dating and correlating rock layers across Europe. The chalk cliffs and quarries of Sussex remain one of the richest fossil-bearing localities for this period.

Scientific Classification

• Species: Calycoceras inerme
• Family: Acanthoceratidae
• Superfamily: Acanthoceratoidea
• Order: Ammonitida
• Geological Stage: Middle Cenomanian, Late Cretaceous

This species is an important zonal fossil for the Cenomanian stage, aiding in biostratigraphic correlation. Its fossil record helps reconstruct ancient marine environments and provides insights into ammonite evolution and diversity.

Morphology and Distinctive Features

The specimen exhibits the key characteristics of Calycoceras inerme:

• Strong ribbing that runs from the umbilicus to the outer whorl, giving the shell a bold, sculptured appearance.
• Prominent tubercles located on the ventrolateral shoulders of the whorls.
• An evolute coiling style, allowing the earlier whorls to remain visible.
• Excellent definition of shell ornamentation, with minimal wear, allowing detailed study and visual appreciation.

These features made the species highly recognisable and help distinguish it from other Cenomanian ammonites.

Depositional Environment

The habitat of Calycoceras inerme was a warm, shallow marine setting with abundant plankton and smaller nektonic organisms. As active predators, these ammonites likely fed on small crustaceans, molluscs, and other invertebrates. After death, their shells sank to the sea floor and were quickly buried in fine chalk sediment, protecting them from scavengers and physical damage, leading to the high-quality preservation seen today.

Collector Value and Display Appeal

This fossil offers a combination of rarity, excellent preservation, and classic provenance from one of the world’s most famous fossil-rich chalk localities. Its striking ribbed pattern and distinctive tubercles make it a visually stunning piece for display, while its precise identification adds academic and historical significance.

Authenticity and Guarantee

All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity. This Calycoceras inerme fossil has been carefully chosen to meet the highest standards for collectors, educators, and enthusiasts alike, ensuring it will be a prized addition to any collection.