This is a rare 5.75-inch MEGATEUTHIS GIGANTEUS belemnite fossil from the Pliensbachian stage of the Jurassic period, discovered in Blockley, United Kingdom. Belemnites were an extinct group of marine cephalopods closely related to modern squid and cuttlefish. Unlike ammonites, belemnites had an internal shell known as the guard, which fossilised over millions of years, leaving behind bullet-shaped remains that are commonly found in Jurassic marine deposits.

Geological Context:

This fossil comes from Lower Jurassic deposits in Blockley, which is well known for its well-preserved marine fossils. The Pliensbachian stage (approximately 187-182 million years ago) was a time of widespread shallow seas, where cephalopods, including belemnites and ammonites, thrived.

The fossil-bearing rock layers in Blockley belong to the Marlstone Rock Formation, a well-studied deposit in England’s Jurassic Coast. This formation is rich in iron-rich sandy limestones, mudstones, and calcareous siltstones, providing an ideal environment for the fossilisation of marine life.

Fossil Type & Species Information:

Belemnites, like MEGATEUTHIS GIGANTEUS, were nektonic predators that actively swam in the Jurassic seas, preying on small fish and invertebrates. Their torpedo-shaped body and streamlined internal skeleton (rostrum or guard) helped them remain stable while moving through the water.

Key characteristics of MEGATEUTHIS GIGANTEUS include:

• A large, robust guard that is significantly thicker than other belemnite species
• A tapered, elongated conical shape, with a pointed posterior end
• Calcite-replaced preservation, maintaining the original structure
• Fine surface striations and growth lines, which provide insight into its growth and environmental conditions

Key Features:

• Authentic MEGATEUTHIS GIGANTEUS fossil belemnite
• Size: 5.75 inches in length
• Age: Approximately 187-182 million years old (Pliensbachian, Jurassic)
• Geological Formation: Marlstone Rock Formation
• Origin: Blockley, United Kingdom
• Well-preserved specimen with fine surface details
• From the Alice Purnell Collection, one of the largest ammonite and fossil collections in the world
• 100 percent genuine specimen with Certificate of Authenticity

Size & Condition:

• Scale Rule / Cube = 1cm – Please refer to the photos for accurate sizing.
• The fossil has been professionally prepared to highlight its natural details.

Why Collect Belemnites?

Belemnites are highly sought-after fossils due to their importance as index fossils, helping geologists date rock layers in the Jurassic and Cretaceous periods. Their unique evolutionary adaptations, including their streamlined internal shell and predatory lifestyle, make them a fascinating addition to any fossil collection.

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