Fossil Bivalve Pholadomya decussata Cretaceous Chalk Marl East Sussex UK COA

Description

Authentic Fossil Bivalve – Pholadomya decussata

This listing presents a rare fossil bivalve, Pholadomya decussata, discovered in the Cretaceous Chalk Marl deposits of Southernham Quarry Pit, East Sussex, United Kingdom. This specimen offers both historical and scientific value, showcasing the remarkable preservation of a marine mollusc that thrived during the age of the dinosaurs. As with all our fossils, this piece is 100% genuine and comes with a Certificate of Authenticity, guaranteeing its provenance. The photographs display the exact fossil you will receive, with a 1 cm scale cube for accurate size reference.

Geological Background

The fossil originates from Chalk Marl formations of the Cretaceous period, a time when much of what is now Britain was covered by warm, shallow seas. These chalky sediments were deposited over millions of years, forming extensive marine layers rich in the remains of invertebrates, including ammonites, belemnites, echinoids, and bivalves such as Pholadomya decussata.

The Chalk Marl of East Sussex is part of the Lower Chalk succession, dating to the early stages of the Late Cretaceous. This environment was dominated by calcareous ooze, slowly accumulating on the seafloor in a relatively stable, low-energy marine setting. Fossils preserved within this formation provide exceptional insights into Cretaceous marine biodiversity and palaeoenvironments.

Taxonomy and Classification

• Kingdom: Animalia
• Phylum: Mollusca
• Class: Bivalvia
• Order: Myoida
• Family: Pholadomyidae
• Genus: Pholadomya
• Species: Pholadomya decussata

The genus Pholadomya is an extinct group of bivalves that flourished during the Mesozoic era. Known for their elongate shells and characteristic sculpture, these molluscs adapted to burrowing lifestyles in soft marine substrates. Their fossils have been documented across Europe and beyond, serving as important tools for stratigraphic correlation.

Morphological Features

The Pholadomya decussata specimen displays the distinctive features of this species, including its elongated shell with strong radial ribs intersecting concentric growth lines, giving a latticed, or “decussate,” appearance from which its name derives. These ribs provided structural strength and aided in burrowing through sediment.

The bivalve’s shell form reflects its adaptation to a burrowing lifestyle within soft seabed muds and marl. Many specimens, including this one, retain exquisite detail, showing fine ridges and growth increments that document seasonal and environmental variations during the Cretaceous seas.

Scientific and Collector Significance

Pholadomya decussata is not only a striking fossil for display but also an important species for scientific study. Its distinct morphology and occurrence within well-dated chalk sequences make it a useful biostratigraphic marker fossil, helping geologists to correlate layers across different sites.

For collectors, this specimen offers a tangible connection to the marine ecosystems of the Cretaceous period in southern England. Its rarity and provenance from Southernham Quarry Pit in East Sussex enhance its desirability, making it a sought-after addition to both private and educational fossil collections.

Provenance and Authenticity

Collected from Southernham Quarry Pit, East Sussex, this fossil has been professionally prepared to highlight its natural detail. It has not been artificially enhanced, ensuring that it remains a genuine and scientifically valuable specimen. Each fossil we sell is accompanied by a Certificate of Authenticity, confirming its geological age, locality, and identification as Pholadomya decussata.

This rare fossil bivalve from the Chalk Marl of the Cretaceous period in East Sussex, UK is an exceptional piece of natural history. With its detailed shell sculpture, clear provenance, and guaranteed authenticity, it represents both a collector’s treasure and an educational specimen that captures the diversity of ancient marine life.