RARE 11″ Puzosia planulata Fossil Ammonite – Greensand, Albian, Cretaceous – Monmouth Beach Lyme Bay Dorset UK – Alice Purnell Collection

Description

An exceptionally large and rare 11-inch specimen of Puzosia planulata, a striking fossil ammonite from the Albian Stage of the Lower Cretaceous, preserved within the Greensand Formation at the classic site of Monmouth Beach, Lyme Bay, Dorset, United Kingdom. This outstanding fossil is part of the respected Alice Purnell Collection, and the photo shows the actual specimen you will receive.

Geological Context:

• Species: Puzosia planulata
• Geological Period: Cretaceous
• Stage: Albian (~113 – 100.5 million years ago)
• Formation: Upper Greensand
• Location: Monmouth Beach, Lyme Bay, Dorset, UK
• Depositional Environment: Shallow marine shelf with glauconitic sandstones and silts, deposited under warm subtropical conditions; part of a widespread marine transgression across southern England during the mid-Cretaceous

Taxonomic Classification:

• Family: Desmoceratidae
• Superfamily: Desmoceratoidea
• Order: Ammonitida
• Suborder: Ammonitina
• First Described By: J. Sowerby, early 19th century (species widely referenced in mid-Cretaceous British ammonite zonation)

Morphological Features:

Puzosia planulata is characterised by a large, involute, discoidal shell with smooth to slightly sinuous ribbing and a compressed whorl section. The flanks are flat to gently rounded, and the venter is typically narrowly rounded or slightly keeled. The shell form suggests a fast-swimming nektonic lifestyle, and this genus is known for wide geographic distribution and zonal consistency.

This specimen features the classic form and preservation associated with Monmouth Beach material, showing the full coiled spiral, strong suture definition, and natural surface texture. Its size makes it a truly rare display-quality fossil.

Stratigraphic and Scientific Significance:

Puzosia planulata is a key taxon in the mid-Albian ammonite biozones, helping define stratigraphic intervals across Europe. Its presence in the Greensand of southern England makes it an important indicator species for marine transgression events in the Early to mid-Cretaceous. The genus Puzosia is widely used in both European and global biostratigraphy.

Additional Details:

• All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity.
• Scale Rule Squares / Cube = 1cm. Please see listing photo for exact dimensions.
• Part of the scientifically documented Alice Purnell Collection.

This is a rare and scientifically valuable ammonite fossil ideal for collectors, educators, or as a museum-grade centrepiece. Its size, provenance, and preservation make it a showcase specimen.

Add this impressive Puzosia planulata to your collection today.