Plagiostoma Fossil Bivalve Jurassic Dorset UK Lower Lias Jurassic Coast Monmouth

Description

Authentic Plagiostoma Fossil Bivalve from the Jurassic Coast

Offered here is a genuine Plagiostoma fossil bivalve from the Lower Lias of the Jurassic Coast, collected from the Monmouth area, Dorset, UK. This specimen has been carefully chosen for its preservation, clarity, and natural presentation. The photographs show the exact fossil you will receive, allowing you to assess quality and character before purchase. Full sizing details are shown in the photos.

This fossil is a genuine specimen and includes a Certificate of Authenticity lifetime guarantee generic card, providing lasting confidence in provenance and collectability.

Geological Formation and Age

This bivalve originates from the Lower Lias Group, deposited during the Early Jurassic Period, approximately 199–191 million years ago. The Lower Lias represents a time when much of southern Britain lay beneath a shallow epicontinental sea. Fine muds and calcareous sediments accumulated on the sea floor, creating conditions ideal for the preservation of marine invertebrates. The Dorset Jurassic Coast is internationally recognised for its continuous geological exposures and rich fossil record, making specimens from this region highly desirable for both scientific and private collections.

Fossil Type and Scientific Context

Plagiostoma is a well-known genus of marine bivalve mollusc that lived attached to or resting on the sea floor during the Jurassic. These bivalves are characteristic components of Lower Jurassic marine faunas and are commonly associated with ammonites, belemnites, and other invertebrates. Fossils of Plagiostoma provide valuable insight into benthic ecosystems of the Early Jurassic and are frequently used to interpret palaeoenvironmental conditions within the Lower Lias.

Morphology and Notable Features

This specimen displays the classic inequivalve shell form typical of Plagiostoma, with a gently curved outline and pronounced radial ornamentation. Growth lines and ribbing may be visible across the shell surface, recording successive stages of the animal’s life. The shell shape reflects adaptation to stable resting or attachment on soft marine substrates. Preservation retains the overall form and surface detail, making the fossil both scientifically informative and visually appealing.

Depositional Environment

During the Early Jurassic, the Monmouth area of the Dorset coast lay beneath a warm, shallow marine environment with relatively low energy conditions. Fine sediments settled slowly on the seabed, allowing bivalves and other organisms to be buried rapidly after death. Periodic low-oxygen conditions reduced scavenging and disturbance, contributing to the preservation of articulated shells and impressions within the Lower Lias sediments. These conditions underpin the exceptional invertebrate fossil record for which the Jurassic Coast is famous.

Collecting, Display, and Educational Value

This Plagiostoma fossil bivalve is well suited for private fossil collections, educational use, museum displays, or decorative presentation. Its classic Jurassic Coast provenance, clear geological context, and recognisable morphology make it an excellent example of Early Jurassic marine life. Bivalves from the Lower Lias are valued for their role in reconstructing ancient sea-floor communities and remain popular with collectors seeking authentic British fossils. Each specimen we offer is individually selected, ensuring you receive a carefully curated and genuine piece of Jurassic marine history from one of the world’s most important fossil coastlines.