Large Xipheroceras and Promicroceras Ammonites Fossil Woodstone Block Jurassic Coast UK

Description

Exceptional Large Xipheroceras and Promicroceras Ammonites in Woodstone Block – Jurassic Coast, Dorset, UK

This outstanding fossil display features beautifully preserved Xipheroceras and Promicroceras ammonites set within their natural Woodstone matrix, collected from the world-famous Black Ven Marls, Lower Lias, Jurassic Coast, at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK. This region is one of the most scientifically significant Early Jurassic fossil localities on Earth, renowned for its abundance and quality of ammonite preservation.

Your exact specimen was discovered by our own team members, Alister and Alison, on 25 November 2025, and subsequently cleaned, prepped, and professionally treated by Alison. You will receive the precise fossil shown in the photographs. A 1 cm scale cube is included for accurate size reference.

All of our fossils are 100% genuine specimens and come with a Certificate of Authenticity.

Geological Setting – Lower Lias, Early Jurassic

This specimen originates from the Lower Lias, deposited during the Early Jurassic period (approximately 199–190 million years ago). The Black Ven Marls and associated Woodstone layers represent a classic marine sedimentary environment rich in ammonites and other early Jurassic fauna.

The ammonites in this block formed in a low-oxygen offshore marine basin, where fine sediments settled slowly, allowing exceptional fossil preservation. The Woodstone is a distinctive, sideritic, iron-rich nodule material that frequently yields beautifully detailed ammonite fossils, often exhibiting sharp ribbing and well-defined shell geometry.

The Fossils – Xipheroceras & Promicroceras

Xipheroceras

These ammonites are typically recognised by their elegant, ribbed shells with pronounced keels and strong ornamentation. Their morphology suggests adaptation for a stable, hydrodynamic swimming lifestyle in open marine waters. Xipheroceras is part of the rich ammonite fauna typical of the Lower Jurassic and often found near the base of the Charmouth Mudstone Formation.

Promicroceras

Promicroceras is one of the most iconic ammonites from the Jurassic Coast, known for its tight, finely ribbed spiral, compact form, and delicate ornamentation. These ammonites are small but highly diagnostic of the Lower Lias. Their symmetrical ribbing and neat coiling make them a favourite among collectors and researchers alike.

Together, these two genera form a striking scientific and aesthetic combination on a single natural block, showcasing the biodiversity of Early Jurassic marine life in this region.

Scientific & Collecting Significance

The Jurassic Coast is a UNESCO World Heritage Site and one of the most important palaeontological locations in the world. The ammonites preserved within its cliffs provide vital insights into Early Jurassic evolution, biostratigraphy, and palaeoenvironments.

Woodstone blocks such as this are sought after by collectors because they preserve fossils in exceptional detail, often showing ribbing, growth chambers, and shell morphology with minimal distortion. Specimens featuring multiple ammonite species in the same natural matrix, especially with a large Xipheroceras, are increasingly rare due to limited accessible exposure.

Authenticity & Presentation

• 100% genuine fossil specimen

• Certificate of Authenticity included

• Professionally prepared by our in-house specialist

• Exact specimen shown in the photos is the one you will receive

• Scale cube = 1 cm (full sizing visible in photos)

This is a rare opportunity to own a scientifically valuable and visually impressive ammonite fossil from one of the most iconic fossil localities in the world.