Description
Genuine Pentacrinites Crinoid Fossil Slab from the Jurassic Coast
This striking Pentacrinites crinoid fossil slab originates from the famous Black Ven Marls of the Lower Lias Formation at Black Ven, Lyme Regis, Dorset, UK, part of the internationally recognised Jurassic Coast World Heritage Site. Dating to the Early Jurassic Period approximately 200–190 million years ago, this fossil preserves the remains of ancient marine echinoderms commonly known as sea lilies.
The specimen is a carefully selected natural fossil slab displaying Pentacrinites crinoid remains, preserved within the original marine sedimentary rock. The photographs show the exact fossil you will receive, allowing collectors to appreciate the preserved structure and natural arrangement of the fossil material.
This fossil includes a Certificate of Authenticity lifetime guarantee generic card, confirming the specimen is a genuine fossil. Please refer to the photographs for full sizing and scale, as they show the exact specimen offered.
Geological Origin – Black Ven Marls and the Lower Lias
The fossil comes from the Black Ven Marls, part of the Lower Lias Group, a sequence of Early Jurassic marine sediments exposed along the Dorset coastline near Lyme Regis. These rocks were deposited during the Hettangian to Sinemurian stages of the Early Jurassic, a time when much of southern Britain was submerged beneath a shallow sea.
The sediments consist mainly of dark marine clays and marls, which accumulated slowly on the sea floor under relatively calm conditions. These environments were ideal for preserving marine organisms that lived within the Jurassic seas.
The Lyme Regis coastline is renowned worldwide for its rich fossil record, which includes:
- Ammonites
- Marine reptiles such as ichthyosaurs and plesiosaurs
- Bivalves and gastropods
- Crinoids
- Fish remains
The Black Ven cliffs are especially famous for producing beautifully preserved fossils due to continual coastal erosion exposing new material.
Pentacrinites Crinoids – Ancient Sea Lilies
The fossils on this slab belong to the genus Pentacrinites, a type of crinoid that flourished in Jurassic seas. Crinoids are marine echinoderms related to modern starfish, brittle stars, and sea urchins, and they possess a distinctive body structure adapted for filter feeding.
Scientific Classification
- Kingdom: Animalia
- Phylum: Echinodermata
- Class: Crinoidea
- Order: Isocrinida
- Family: Pentacrinitidae
- Genus: Pentacrinites
Unlike some earlier crinoids that lived anchored to the seabed, many Jurassic Pentacrinites species attached themselves to floating objects such as driftwood. This lifestyle allowed them to extend into the water column where food particles were abundant.
Morphology and Distinctive Features
Crinoids possess a highly recognisable anatomy composed of several main components. The fossil slab preserves parts of the stem and skeletal plates typical of Pentacrinites.
Characteristic features include:
- Pentagonal columnal segments forming the stem
- A central body known as the calyx
- Feathery arms used for suspension feeding
- Interlocking calcite plates forming the skeleton
- Distinct fivefold radial symmetry typical of echinoderms
The pentagonal shape of the stem segments is responsible for the name Pentacrinites, meaning “five-rayed lily.” These columnals often break apart after death and accumulate in sedimentary layers where they fossilise in clusters or slabs.
Early Jurassic Marine Environment
During the Early Jurassic, the seas covering southern Britain supported rich marine ecosystems filled with invertebrates and vertebrate predators. The waters were relatively warm and contained abundant plankton and organic material.
Within these ecosystems, crinoids such as Pentacrinites functioned as suspension feeders, capturing microscopic food particles drifting through the water using their feather-like arms.
The environment also supported:
- Ammonites drifting through the open water
- Marine reptiles hunting fish and cephalopods
- Bivalves and gastropods living within the sediment
- Crustaceans and echinoderms inhabiting the sea floor
Crinoids formed an important part of these ecosystems, contributing to the biodiversity of Jurassic marine life.
Fossil Preservation in Marine Marl
The exceptional preservation of Pentacrinites fossils is due to the fine-grained marl sediments of the Lower Lias sea floor. When crinoids died, their skeletal plates and stem segments settled onto the seabed and were quickly buried by soft sediment.
Over millions of years, the original calcite skeleton mineralised within the surrounding rock, preserving the structure of the crinoid columns and skeletal plates.
The fossil slab retains the natural arrangement of these ancient echinoderm remains, offering a genuine snapshot of life in the Early Jurassic sea.
Certificate of Authenticity
This fossil specimen includes a Certificate of Authenticity lifetime guarantee generic card, confirming the fossil is genuine.
Each specimen is carefully selected to ensure authenticity and display quality for collectors and enthusiasts.
A Classic Jurassic Coast Fossil for Collectors
Fossils from Lyme Regis and the Jurassic Coast are among the most historically significant in palaeontology, having contributed greatly to the early development of fossil science. Pentacrinites crinoids are iconic fossils from the Lower Lias and remain highly sought after by collectors.
This Pentacrinites crinoid fossil slab from Black Ven represents an authentic piece of Jurassic marine life preserved within the famous fossil-bearing cliffs of Dorset, making it an excellent addition to any fossil collection, natural history display, or geological cabinet.
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