RARE Aegasteroceras crassum Ammonite Fossil – Lower Jurassic, Frodingham Ironstone Formation, Scunthorpe UK

Description

This listing features a rare ammonite fossil of the species Aegasteroceras crassum, discovered in the Frodingham Ironstone Formation at Conesby Quarry, Scunthorpe, North Lincolnshire, UK. This specimen comes from the Lower Lias Group, specifically the Denotatus Subzone of the Obtusum Zone, within the Lower Jurassic.

Fossil Type & Species:

• Type: Ammonite (Extinct Cephalopod Mollusc)
• Species: Aegasteroceras crassum
• Recognised by its broad, thick shell and bold ribbing

Geological Context:

• Period: Mesozoic Era
• System: Jurassic
• Epoch: Early Jurassic
• Stage: Hettangian to Sinemurian
• Zone: Obtusum Zone
• Subzone: Denotatus Subzone
• Formation: Frodingham Ironstone Formation (Lower Lias Group)
• Depositional Environment: Shallow marine shelf environment, rich in iron minerals. This fossil was preserved in ironstone layers formed in quiet, low-energy marine conditions.

Morphological Features:

• Thick, robust shell (hence ‘crassum’) with pronounced ribs
• Involute coiling, giving a compact appearance
• Deep umbilicus and moderate whorl compression
• Shell surface may show mineralisation typical of ironstone preservation

Scientific Importance:

• Aegasteroceras crassum is a key ammonite species used for high-resolution stratigraphic correlation within the Denotatus Subzone of the Lower Jurassic
• Specimens from Scunthorpe are known for their detail and preservation, making them important for both biostratigraphy and palaeontological collections

Locality Information:

• Conesby Quarry, Scunthorpe, North Lincolnshire, England – a classic and historically significant site for Lower Jurassic ammonite fossils from the Frodingham Ironstone Formation

Authenticity & Display:

All of our fossils are 100% Genuine Specimens and come with a Certificate of Authenticity. This listing includes photographs of the actual specimen you will receive. Please refer to the image for full sizing, with the scale cube = 1cm.

This is a stunning and well-documented specimen of Aegasteroceras crassum, ideal for collectors, educators, or enthusiasts of Lower Jurassic marine life.

Add an authentic piece of British Jurassic history to your collection—preserved for over 190 million years!