Description
Psiloceras planorbis Fossil Ammonite with Stand – Blue Lias, Jurassic, Watchet, Somerset, UK
This genuine Psiloceras planorbis fossil ammonite with stand is a carefully chosen Jurassic specimen from the famous Blue Lias deposits of Watchet, Somerset, UK. Psiloceras planorbis is one of the most important ammonites in British Jurassic palaeontology, widely recognised as a key fossil from the very beginning of the Jurassic Period. This specimen comes with a display stand, making it ideal for a fossil cabinet, natural history collection, educational display, desk feature or geology-themed gift.
This fossil is the actual specimen shown in the photo, so the piece you see is the fossil you will receive. Full sizing can be seen in the photo. It is supplied as a genuine fossil specimen and includes a Certificate of Authenticity lifetime guarantee generic card.
Your specimen was discovered by our own team members, Alister and Alison, on 29 June 2026 and has been cleaned, prepped and treated by Alison.
Fossil Type and Species
This specimen is Psiloceras planorbis, an ammonite species from the earliest Jurassic. Ammonites were extinct marine cephalopods related to modern squid, cuttlefish and nautilus. They lived in coiled shells divided internally into chambers, with the animal occupying the final body chamber while the earlier chambers helped regulate buoyancy in the ancient sea.
Psiloceras is especially well known for its relatively simple, smooth to lightly ornamented shell form. Compared with many later Jurassic ammonites, Psiloceras planorbis often has a more open, rounded coil, with gently curved whorls and subtle ribbing or growth lines depending on preservation. Its clean planispiral shape makes it a classic and highly collectable ammonite for anyone interested in the start of the Jurassic fossil record.
Geological Age and Blue Lias Formation
This fossil comes from the Blue Lias, one of the most famous fossil-bearing geological units in the UK. The Blue Lias consists of alternating beds of limestone and shale, deposited in a shallow marine environment during the latest Triassic to earliest Jurassic. The Watchet coast of Somerset is particularly well known for its Lower Jurassic exposures, where ammonites, marine reptiles, bivalves and other fossils can be found within the layered coastal rocks.
Psiloceras planorbis is strongly associated with the Planorbis Zone, an important biostratigraphic marker at the base of the Jurassic. The appearance of Psiloceras planorbis has historically been used to help define the beginning of the Jurassic System in Britain. This makes the species especially significant, not only as a display fossil, but also as a scientifically meaningful ammonite from a key moment in Earth history.
Classification and Scientific Interest
Psiloceras planorbis belongs to the ammonite order Ammonitida, within the family Psiloceratidae. It is part of an early Jurassic ammonite lineage that appeared after the end-Triassic extinction event, when marine ecosystems were reorganising and new ammonite groups were becoming established. Because of this, Psiloceras is often valued by collectors as one of the classic ammonites representing the dawn of the Jurassic seas.
The species name planorbis refers to its flattened, rounded coiling form. The genus Psiloceras was formally established by Alpheus Hyatt, and Psiloceras planorbis remains one of the most familiar species associated with the earliest Jurassic ammonite zones of Britain.
Morphology and Preservation
This Psiloceras planorbis ammonite displays the typical coiled shell shape that makes ammonites so recognisable. Depending on the exact preservation, features may include a rounded whorl profile, visible coiling, natural shell outline, sediment infill, subtle surface markings and mineralised detail from the surrounding Blue Lias matrix. Fossils from the Watchet area can vary in colour and texture according to the limestone, shale and mineral conditions in which they were preserved.
The included stand enhances the specimen’s display value, allowing the fossil to be presented upright or at an attractive viewing angle. This makes it a strong choice for collectors who want a ready-to-display British Jurassic ammonite with clear locality and geological context.
Authenticity, Locality and Display
This is a genuine Psiloceras planorbis ammonite fossil from Watchet, Somerset, supplied with a Certificate of Authenticity lifetime guarantee generic card. It has been personally discovered, cleaned, prepped and treated by our own team, adding excellent provenance for collectors who value locality and collection history.
The fossil is ideal for collectors of British ammonites, Blue Lias fossils, Lower Jurassic marine fossils, display specimens, educational geology pieces and natural history gifts. Natural surface texture, matrix, mineral staining, small chips, preparation marks or age-related features may be present, all of which are normal characteristics of genuine fossil specimens from classic coastal Jurassic deposits.
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