Description
Pentacrinites Crinoid Fossil Slab – Jurassic Coast, Lyme Regis, Dorset
This impressive Pentacrinites crinoid fossil slab is a genuine specimen from the famous Black Ven Marls of Charmouth, Lyme Regis, located along the UNESCO World Heritage Jurassic Coast in Dorset, UK. Dating to the Lower Lias of the Early Jurassic period, approximately 199–190 million years ago, this fossil captures a remarkable example of ancient marine life preserved within its natural matrix.
Carefully selected for its scientific and visual appeal, this slab features multiple crinoid stem elements preserved in situ, offering a striking display of fossilised “sea lilies.” The exact specimen shown in the photographs is the one you will receive and includes a Certificate of Authenticity lifetime guarantee generic card.
Geological Context – Black Ven Marls, Lower Lias Formation
The Black Ven Marls are part of the Lower Jurassic Lias Group, a sequence of clay-rich marine sediments deposited in a shallow epicontinental sea covering much of southern England during the Early Jurassic. These sediments are renowned for their exceptional fossil preservation, particularly of marine reptiles, ammonites, and echinoderms such as crinoids.
The depositional environment was relatively calm, allowing fine-grained sediments to accumulate on the seabed. Periodic low-oxygen conditions limited decay and disturbance, enabling delicate skeletal structures such as crinoid stems to be preserved in fine detail.
This fossil is typically associated with the Sinemurian stage, a time when crinoid communities flourished across the seafloor.
Fossil Identification – Pentacrinites (Class: Crinoidea)
Pentacrinites is a genus of crinoid, a group of marine echinoderms related to modern starfish and sea urchins. Belonging to the class Crinoidea and order Isocrinida, these organisms are often referred to as “sea lilies” due to their plant-like appearance.
Pentacrinites is characterised by long, segmented stems composed of pentagonal columnals, which anchored the animal to the seabed or floating debris. At the top of the stem, feathery arms would have extended into the water column to capture plankton and organic particles.
Morphology and Notable Features
This fossil slab displays classic Pentacrinites characteristics and offers a visually engaging natural arrangement:
- Multiple articulated stem segments preserved within the slab
- Distinct pentagonal columnals forming the crinoid stem
- Natural clustering of stems, suggesting a colony or accumulation
- Clear segmentation and alignment of ossicles
- Preservation within original Jurassic marine matrix
The repeating pentagonal structure is a defining feature of Pentacrinites, giving rise to its name and making it easily recognisable among fossil crinoids.
Depositional Environment and Fossil Formation
During the Early Jurassic, the Lyme Regis region was submerged beneath a warm, shallow sea rich in marine biodiversity. Crinoids such as Pentacrinites lived either anchored to the seabed or attached to floating driftwood, forming dense colonies.
Following death or disarticulation, the skeletal elements settled onto the seabed. In many cases, storm events or gentle currents caused accumulations of crinoid stems, which were then rapidly buried by fine sediment.
Low oxygen conditions at the seabed helped preserve these delicate structures, while gradual mineralisation replaced the original calcite skeleton with more stable minerals, resulting in the fossil slab seen today.
Scientific and Collecting Significance
Pentacrinites fossils from the Jurassic Coast are highly valued due to their clear morphology and historical importance. Crinoid slabs provide insight into ancient marine ecosystems and the behaviour of echinoderm communities during the Early Jurassic.
Lyme Regis is one of the most famous fossil localities in the world, known for its contributions to early palaeontology. Fossils from this region are widely recognised for their quality, provenance, and scientific significance.
Multi-specimen crinoid slabs are especially desirable for collectors, as they present a natural snapshot of prehistoric life rather than a single isolated fossil.
Authenticity and Presentation
This fossil is a 100% genuine Pentacrinites crinoid specimen and includes a Certificate of Authenticity lifetime guarantee generic card. The fossil shown in the photographs is the exact piece you will receive.
Full sizing can be confirmed via the listing images, allowing you to clearly assess the scale and detail of the specimen.
Ideal for Collectors, Display, or Educational Use
This Pentacrinites fossil slab is an outstanding addition to any fossil collection, offering both visual impact and scientific value. Perfect for collectors, educators, or as a unique natural history display piece, it represents a genuine fragment of Jurassic marine life from one of the most celebrated fossil locations in the world.
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