Multi Ammonite Block Promicroceras Cymbites Asteroceras Fossil Wood Jurassic Coast UK

Description

Multi-Ammonite Block with Fossil Wood – Promicroceras, Cymbites and Partial Asteroceras

This striking multi-species ammonite block showcases a natural association of Promicroceras, Cymbites, and a partial Asteroceras, accompanied by beautifully preserved fossil wood fragments. The specimen originates from the renowned Black Ven Marls, Lower Lias, Jurassic Coast, collected at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, UK, one of the most scientifically important Early Jurassic fossil localities in the world.

Your exact specimen was discovered by our team members, Alister and Alison, on 25 November 2025, and has been expertly cleaned, prepared, and treated by Alison. The photographs show the actual fossil you will receive, and a 1 cm scale cube is included to provide a clear size reference.

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

Geological Origin – Lower Lias, Early Jurassic

This fossil assemblage was preserved in the Lower Lias, dating to the Early Jurassic period, approximately 199–190 million years old. The Black Ven Marls are part of the celebrated Charmouth Mudstone Formation, a richly fossiliferous sequence deposited in a calm, offshore marine environment.

The sediments in this region were laid down in a low-oxygen marine basin, where fine muds accumulated gradually, enabling delicate organisms to fossilise with exceptional detail. Occasional driftwood became waterlogged and settled onto the seafloor, where it slowly mineralised into the distinctive fossil wood often found at Charmouth. This creates remarkable mixed assemblages such as the one presented here, capturing a moment of ancient seafloor ecology.

Promicroceras – Finely Ribbed Elegance

Promicroceras is one of the most iconic ammonites of the Lower Lias. Known for its tight, finely ribbed spiral, small size, and consistent ornamental pattern, it is highly valued by collectors. Its clean, symmetrical coiling and crisp ribbing are frequently used in biostratigraphic work, helping geologists interpret layer sequences across the Jurassic Coast.

This block includes multiple Promicroceras individuals, highlighting their abundance and characteristic preservation in the Black Ven Marls.

Cymbites – Distinctive Shell Geometry

Cymbites ammonites are easily recognised by their smooth inner whorls, broad ribs on the outer coils, and compact, rounded form. Their morphology suggests a nektonic lifestyle in the open water column. In the Lower Lias, Cymbites species contribute greatly to understanding ammonite distribution across the early Jurassic seas.

Their presence here adds scientific value and visual interest, creating a well-balanced multi-species display.

Partial Asteroceras – A Classic Jurassic Giant

Even as a partial specimen, Asteroceras remains impressive. This genus is one of the more sizeable ammonites of the Lower Jurassic, typically displaying bold ribs and robust shell structure. The inclusion of a partial Asteroceras in this block provides a contrast in scale and morphology against the smaller Promicroceras and Cymbites specimens, illustrating the diversity of ammonites present within the same stratigraphic horizon.

Fossil Wood – A Rare and Beautiful Association

The fossil wood preserved within the block adds a natural and scientifically valuable dimension. These mineralised plant remains represent driftwood that settled into the marine basin during the Early Jurassic. Their presence within an ammonite assemblage creates a snapshot of the interplay between terrestrial and marine environments along the ancient coastlines of what is now Dorset.

Authenticity, Preparation & Presentation

• 100% genuine fossil specimen

• Certificate of Authenticity included

• Professionally prepared by Alison

• Discovered by our own team members at Charmouth

• Exact specimen shown in the photographs

• Scale cube = 1 cm for accurate sizing

This multi-ammonite block with fossil wood is a superb, naturally occurring display piece from the UK’s world-famous Jurassic Coast, offering both scientific significance and beautiful visual appeal.