Description
Rare Pleydellia comata Fossil Ammonite
This is a carefully chosen Pleydellia comata fossil ammonite from the Aalenian stage of the Jurassic Period, collected from Calvados, France. This attractive French Jurassic ammonite is a genuine fossil specimen and comes from the Alice Purnell Collection. The photograph shows the actual fossil you will receive, making this an excellent choice for collectors who value natural detail, accurate representation and provenance.
This fossil is supplied with a generic Certificate of Authenticity card with lifetime guarantee, confirming it as a genuine specimen. Full sizing can be seen in the photo, allowing the buyer to assess the scale, preservation and display quality of the piece before purchase.
Geology and Jurassic Age
The Aalenian is the earliest stage of the Middle Jurassic, dating to approximately 174 to 170 million years ago. During this period, much of western Europe was covered by warm shallow seas, with marine sediment being deposited across what is now France. Calvados, in Normandy, is well known for Jurassic marine deposits that have produced ammonites and other marine fossils from ancient seabed environments.
This Pleydellia comata ammonite represents life from a time when marine reptiles, fish, belemnites, bivalves and ammonites inhabited Jurassic seas. Ammonites are especially important fossils because their rapid evolution and widespread distribution make them valuable for dating Jurassic rocks and correlating geological layers between different regions.
Fossil Type and Species
This specimen is an ammonite, an extinct marine cephalopod related to modern squid, cuttlefish and nautilus. Ammonites lived inside coiled, chambered shells and used their internal chambers for buoyancy control. The living animal occupied the final body chamber, while earlier chambers helped regulate its position in the water column.
Species: Pleydellia comata
Genus: Pleydellia
Family: Hammatoceratidae
Superfamily: Hammatoceratoidea
Order: Ammonitida
Class: Cephalopoda
Phylum: Mollusca
Pleydellia is a well-known Jurassic ammonite genus recognised for its elegant coiled shell form and fine ribbing. Species within this group are of interest to collectors and palaeontology enthusiasts because they occur close to an important interval in Jurassic ammonite evolution and biostratigraphy. Pleydellia ammonites are often associated with finely ornamented shells, a compressed whorl profile and a balanced spiral form that makes them attractive display fossils.
Morphology and Display Features
Pleydellia comata is valued for its classic ammonite appearance, showing the natural spiral geometry that makes ammonites among the most recognisable fossils in the world. The shell form is typically neat and rounded, with visible whorls that record the growth of the animal throughout life. Ribbing and shell ornamentation are important features in ammonite identification, and these details help distinguish different genera and species within Jurassic ammonite faunas.
The coiled shell structure reflects both biological efficiency and evolutionary success. As the ammonite grew, new shell material was added around the outer whorl, creating the iconic spiral shape. This natural form gives the fossil strong visual appeal for display in a cabinet, study, educational collection or natural history setting.
Calvados, France Fossil Locality
Calvados in Normandy, France, is an important region for Jurassic fossils, particularly marine invertebrates preserved in sedimentary rocks laid down in ancient seas. The fossil-bearing deposits of this region include limestones, marls and clays that formed from marine sediment accumulating on the seafloor. These conditions allowed shells from ammonites and other marine animals to be buried and preserved over millions of years.
French Jurassic ammonites are highly collectable because they combine geological interest, attractive preservation and strong scientific value. A specimen from Calvados carries a desirable locality connection and represents one of the classic fossil-producing regions of Europe.
Authenticity and Collection Provenance
This Pleydellia comata fossil ammonite is from the Alice Purnell Collection and has been selected as a quality collector’s specimen. The photo shows the actual fossil being offered, so the buyer can clearly see the form, preservation, matrix, colour, surface texture and natural features of the piece.
As with all genuine fossils, natural cracks, mineralisation, surface wear, matrix, preparation marks and variations in colour or texture may be present. These features are part of the fossil’s natural history and add to its individuality. This is a genuine fossil ammonite supplied with a Certificate of Authenticity lifetime guarantee generic card, making it suitable for fossil collectors, geology enthusiasts, educational use, natural history displays and anyone interested in the ancient marine life of Jurassic France.
