Cardioceras excavatum Fossil Ammonite Lower Oxfordian Jurassic Weymouth Dorset United Kingdom Authentic

Description

This listing features an authentic Cardioceras excavatum ammonite fossil from the Lower Oxfordian stage of the Jurassic period (around 163–160 million years ago). Discovered in Weymouth, Dorset, United Kingdom, this specimen comes from one of the most famous Jurassic fossil localities in the world—the Jurassic Coast, a UNESCO World Heritage Site. With its ribbed shell, characteristic keel, and finely preserved details, Cardioceras excavatum represents a scientifically important ammonite species. The specimen pictured is the exact fossil you will receive, photographed with a 1 cm scale cube for accurate size reference. Every fossil we supply is 100% genuine and is accompanied by a Certificate of Authenticity.

Geological and Stratigraphic Context

This ammonite originates from the Lower Oxfordian stage, which marks the beginning of the Upper Jurassic. During this time, the Weymouth Bay area was part of a warm, shallow sea environment, rich in marine life such as ammonites, belemnites, bivalves, and marine reptiles. The sediments in this region, predominantly clays and limestones, provided excellent preservation conditions for marine fossils.

Cardioceras excavatum belongs to the family Cardioceratidae within the superfamily Perisphinctoidea and is part of the order Ammonitida. This group of ammonites is extremely valuable for biostratigraphy, as their rapid evolution and wide distribution make them excellent index fossils, used to subdivide and correlate Jurassic strata across Europe. The excavatum species is closely tied to the Cardioceras cordatum Zone of the Oxfordian, a key biozone within the Jurassic system.

Morphological Features

The fossil displays the classic features of Cardioceras:

• Coiling: Moderately involute shell with inner whorls partly obscured.
• Ribbing: Strong, sharp ribs running across the flanks, often bifurcating as they cross the shell.
• Keel: A distinct keel along the venter, enhancing both visual appeal and hydrodynamic function.
• Whorl Section: Subcompressed shape with curved flanks and prominent ribbing, producing a striking ornamented profile.
• Suture Lines: Intricate suture patterns, typical of advanced ammonites, may be visible on well-preserved areas.

These features not only help palaeontologists identify the species but also give insight into its ecology as a nektonic predator, capable of agile movement in the Jurassic seas.

Scientific and Collector Importance

Cardioceras excavatum is of major scientific interest because of its role in refining Oxfordian stratigraphy. Specimens like this one help geologists accurately date Jurassic deposits, making them essential reference points in the fossil record.

For collectors, this ammonite offers:

• Historical significance from one of the most iconic fossil localities in Britain.
• Excellent preservation of diagnostic ammonite features.
• Scientific value as a zonal fossil within the Oxfordian.
• A unique chance to own a specimen that connects directly to the global Jurassic story.

Key Details

• Species: Cardioceras excavatum
• Age: Lower Oxfordian, Jurassic (~163–160 million years old)
• Location: Weymouth, Dorset, United Kingdom
• Order: Ammonitida
• Superfamily: Perisphinctoidea
• Family: Cardioceratidae
• Features: Strong ribbing, distinct keel, subcompressed whorl section, complex sutures
• Authenticity: 100% genuine fossil with Certificate of Authenticity
• Scale Reference: 1 cm cube shown in photographs for accurate sizing

This rare Cardioceras excavatum ammonite fossil from Weymouth, Dorset is an excellent opportunity to add an authentic and scientifically valuable piece of Jurassic heritage to your collection. Its strong ribbing and distinctive morphology make it a striking display specimen and a true piece of palaeontological history.

Scale cube = 1 cm. Please see photographs for full sizing details.