#Blue Lias bivalve fossil

[uk-fossils]

Gryphaea arcuata Fossil Bivalve, Blue Lias Formation, Jurassic UK | Frampton-on-Severn Gloucestershire + COA

Gryphaea arcuata Fossil Bivalve – Blue Lias Formation, Lower Jurassic, Frampton-on-Severn, Gloucestershire, England

This beautifully curved bivalve fossil is a classic example of Gryphaea arcuata, a member of the extinct oyster family that thrived in Jurassic seas. Commonly referred to as a “Devil’s Toenail” due to its curled shell shape, this specimen was collected from the famous Blue Lias Formation at Frampton-on-Severn, in Gloucestershire, England.

Fossil Type & Species:

Type: Invertebrate Fossil (Bivalve – Oyster)

Species: Gryphaea arcuata

Phylum: Mollusca

Class: Bivalvia

Order: Ostreoida

Superfamily: Ostreoidea

Family: Gryphaeidae

Described by: Lamarck, 1801

Geological & Stratigraphic Details:

Location: Frampton-on-Severn, Gloucestershire, UK

Formation: Blue Lias Formation

Geological Stage: Lower Jurassic (Hettangian–Sinemurian)

Age: ~201–190 million years ago

Biozone: Planorbis or Bucklandi zones, common to basal Jurassic marine sequences

Depositional Environment: Shallow marine shelf, typically low-energy, muddy seafloor ideal for benthic bivalves like Gryphaea

Morphology & Features: This Gryphaea arcuata specimen shows:

Distinctively curved, thick lower valve (the larger, more robust part of the shell)

Smaller, flatter upper valve which often detached during fossilisation

Fine growth lines and concentric ridges visible across the surface

Natural preservation in a pale grey to blue-grey tone from the Blue Lias limestone matrix

Classic “Devil’s Toenail” shape, iconic in UK fossil heritage

Notable: Gryphaea arcuata is one of the most famous and easily recognisable fossils from Britain’s Jurassic Coast and inland exposures like the Severn Estuary. Often used as a teaching specimen and found in museum collections worldwide, it provides key insight into early Jurassic marine ecology.

Specimen Details:

Origin: Frampton-on-Severn, Gloucestershire, UK

Species: Gryphaea arcuata

Fossil Type: Bivalve Shell (Oyster)

Geological Stage: Lower Jurassic

Formation: Blue Lias

Size Reference: Scale rule square = 1cm (see listing photo for full sizing)

Note: The specimen shown is the exact one you will receive

Authenticity & Quality: We guarantee all fossils are 100% genuine. This piece is professionally selected and comes with a Certificate of Authenticity. No reconstruction or artificial alteration has been applied.

Why Choose This Fossil? Perfect for:

Beginners and seasoned fossil collectors alike

Educational or scientific use

Natural history displays

Iconic UK fossil souvenirs and gifts

Shipping & Packaging: We use eco-conscious, secure packaging and offer tracked global shipping. Every item is carefully wrapped to ensure safe delivery.

Add a true Jurassic classic to your collection with this authentic Gryphaea arcuata fossil from the Blue Lias of Gloucestershire.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.