Rare 5″ Cadoceras Fossil Ammonite, Lower Callovian Jurassic, Hackness Yorkshire UK, Genuine with COA

Description Offered here is a Rare 5″ Fossil Ammonite of Cadoceras sp., originating from the Lower Callovian Stage of the Jurassic Period, discovered near Hackness, North Yorkshire, United Kingdom — a historically important fossil locality within the Cleveland Basin. The specimen shown in the photographs is the actual item you will receive, selected for its preservation quality and scientific importance. Scale Rule Squares / Cube = 1cm — please refer to the image for full sizing accuracy. Key Geological and Scientific Information: Genus: Cadoceras Fossil Type: Ammonite (extinct marine cephalopod) Geological Period: Jurassic Stage: Lower Callovian (Middle Jurassic) Location: Hackness, near Scarborough, North Yorkshire, England, UK Formation: Lower part of the Oxford Clay or upper part of the Kellaways Beds (varies locally) Approximate Age: ~165–164 million years ago Order: Ammonitida Superfamily: Stephanoceratoidea Family: Cardioceratidae First Described By: Friedrich August Quenstedt, mid-19th century Morphological Features: Ammonites from the genus Cadoceras are characterised by their broad, involute, and strongly ribbed shells. The ribs often bifurcate from a strong umbilical shoulder and sweep across the flanks to the venter, sometimes forming a slight keel. Cadoceras species often exhibit complex suture patterns and can reach medium to large sizes. This specimen displays beautifully defined ribbing and clear whorl geometry, typical of the genus. Biozone and Stratigraphy: While Cadoceras is not a primary zone fossil, it is frequently found within the Macrocephalites gracilis Zone and Cadoceras sublaevis Subzone in the Lower Callovian. It is used by palaeontologists to correlate strata within northern Europe, particularly within the Yorkshire coastal and inland sections. Depositional Environment: The fossil formed in a low-energy marine shelf environment, typical of the Kellaways Beds and Oxford Clay Formation, composed mainly of silty clays and fine mudstones deposited under anoxic sea-floor conditions. These settings provided ideal conditions for fossil preservation, especially of cephalopods like ammonites. Scientific Importance: The genus Cadoceras plays an important role in the biostratigraphy of the Middle Jurassic and is a representative of the Cardioceratidae family, known for their evolutionary radiation in Boreal and Sub-Boreal marine settings. This fossil is not only visually appealing but also has palaeontological relevance for understanding Jurassic faunal turnover and ammonite dispersal. Authenticity & Quality Assurance: All of our fossils are 100% genuine, ethically sourced, and carefully prepared. Each purchase includes a Certificate of Authenticity confirming the fossil’s identity and provenance. This 5″ Cadoceras ammonite is a visually striking and scientifically significant addition to any fossil collection, museum-quality display, or educational exhibit. Let us know if you would like a printed display card or bundled educational content with your order.