Description
Authentic Hildoceras bifrons Fossil Ammonite from Whitby, UK
This listing offers a beautiful Hildoceras bifrons fossil ammonite, discovered in the Middle Lias deposits of the Jurassic period at Runswick Bay near Whitby, United Kingdom. The specimen is a carefully selected piece that has been photographed in detail, with the exact fossil shown being the one you will receive. Each fossil is supplied with a Certificate of Authenticity, confirming that it is a 100% genuine specimen sourced from one of the UK’s most famous fossil localities.
Geological Age and Locality
This ammonite comes from the Middle Lias (Lower Jurassic) strata, dating back approximately 174–182 million years. The Whitby coastline, including Runswick Bay, is part of the world-renowned Jurassic Coast of Yorkshire, where alternating beds of shales, mudstones, and iron-rich nodules preserve an incredible range of marine fossils. These layers represent ancient seabeds from a shallow, warm epicontinental sea that covered northern Europe during the Early Jurassic.
Scientific Classification
- Species: Hildoceras bifrons
- Genus: Hildoceras
- Family: Hildoceratidae
- Superfamily: Hildoceratoidea
- Order: Ammonitida
- Class: Cephalopoda
- Age: Middle Lias, Lower Jurassic
- Locality: Runswick Bay, Whitby, North Yorkshire, UK
This species was formally described by French naturalist Alcide d’Orbigny in 1846, and it is now recognised as one of the most iconic ammonites from the Whitby area.
Morphological Features
Hildoceras bifrons is particularly distinctive due to its elegant coiled shell and striking ribbed ornamentation. Notable traits of this species include:
- Strongly ribbed whorls with bifurcating ribs that split as they cross the flanks.
- A compressed and flattened shell shape with a keeled venter.
- Growth lines and suture patterns that highlight its cephalopod anatomy.
- Medium to large adult size, with some specimens reaching impressive diameters.
The ribbed ornamentation of Hildoceras bifrons is a defining characteristic, making it a highly recognisable ammonite for both collectors and palaeontologists.
Biozone and Stratigraphic Importance
Hildoceras bifrons is the index species of the Bifrons Biozone, a key stratigraphic marker used by geologists to correlate Middle Lias deposits across Europe. The abundance and distinct morphology of this ammonite make it one of the most important guide fossils for the Lower Jurassic, particularly within the Toarcian stage. Its presence allows for precise dating of the rock layers in which it is found.
Depositional Environment
The sediments of Runswick Bay were deposited in a shallow marine environment, where fine-grained muds and clays settled on the seabed. Periods of low oxygen on the seafloor helped to preserve the shells of ammonites, belemnites, fish, and marine reptiles. Over millions of years, these sediments lithified into the shales and nodules that today form the cliffs of Whitby, continuously yielding world-class fossils.
Collector’s Value and Scientific Interest
Owning a Hildoceras bifrons ammonite connects collectors with one of the most significant fossil species in Jurassic palaeontology. Its scientific value as an index fossil, coupled with its striking ribbed beauty, makes it a prized addition to any fossil collection. Specimens from Whitby are especially sought after due to their exceptional preservation and historical importance in the study of Jurassic stratigraphy.
Item Details and Authenticity
- Fossil Type: Hildoceras bifrons ammonite
- Age: Middle Lias, Lower Jurassic (approx. 174–182 million years)
- Location: Runswick Bay, Whitby, United Kingdom
- Condition: Well-preserved with characteristic ribbing and keel
- Scale: Rule squares/cube = 1 cm (please see photographs for full sizing)
- Certificate: Includes a Certificate of Authenticity
- Specimen Shown: The exact fossil pictured is the one supplied
This Hildoceras bifrons fossil ammonite from Whitby is an exceptional specimen that combines geological history, scientific importance, and natural beauty in a single piece. Perfect for serious fossil collectors, educational purposes, or as a unique natural display item.
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