Double Androgynoceras Ammonite Green Nodule Jurassic Lyme Regis Dorset UK Lower Lias

Description

Double Androgynoceras Ammonite Green Nodule from the Jurassic Coast

Offered here is a striking double Androgynoceras ammonite nodule, preserving two large ammonites measuring approximately 3.75 inches and 3 inches, naturally enclosed within a classic green ammonite nodule. This specimen originates from the renowned Green Ammonite Beds at Stonebarrow Cliff, Charmouth, Lyme Regis, Dorset, part of England’s world-famous Jurassic Coast. The photographs show the exact fossil you will receive, carefully selected for balance, preservation, and visual impact. Full sizing details can be seen in the photos.

This fossil is a genuine specimen and is supplied with a fully hand-signed Premium Certificate of Authenticity, offering the highest level of assurance in provenance and long-term collectability.

Geological Formation and Age

This specimen comes from the Lower Lias Group, deposited during the Early Jurassic Period, approximately 199–191 million years ago, within the Sinemurian Stage. The Green Ammonite Beds are a distinctive horizon within the Lower Lias, characterised by hard, iron-rich limestone nodules that weather free from softer surrounding sediments. These nodules formed around decaying organic matter on the Jurassic sea floor, creating ideal conditions for preserving ammonites in three dimensions. Stonebarrow Cliff is one of the most important exposures of these beds and is internationally recognised for producing high-quality ammonite nodules.

Fossil Type, Species, and Scientific Context

Androgynoceras is an Early Jurassic ammonite genus belonging to the Order Ammonitida, Superfamily Eoderoceratoidea, and Family Eoderoceratidae. It is a characteristic ammonite of the Lower Lias and is well known for its bold ribbing and robust shell form. Androgynoceras is associated with Lower Jurassic ammonite biozones used in biostratigraphic correlation, making specimens from this genus scientifically informative as well as visually impressive. Double ammonite nodules of this size are particularly uncommon and highly sought after.

Morphology and Notable Features

The two Androgynoceras ammonites display classic planispiral coiling with strong, well-defined ribs radiating across the flanks. The shells are robust and evenly proportioned, reflecting adaptation to active swimming in open marine conditions. Preservation within the green limestone nodule protects the ammonites and enhances three-dimensional detail. The natural green coloration of the nodule, caused by iron minerals, creates a striking contrast with the fossilised shells and makes this piece especially attractive for display.

Depositional Environment

During the Early Jurassic, the Charmouth and Lyme Regis area lay beneath a warm, shallow epicontinental sea rich in ammonites, belemnites, fish, and marine reptiles. Periodic storm events caused ammonite shells to accumulate on the sea floor, where early burial within carbonate-rich sediments led to nodule formation. Low-oxygen conditions within the sediment reduced scavenging and decay, allowing ammonites to be preserved intact within hard limestone nodules such as this one.

Rarity, Display, and Collecting Value

This double Androgynoceras ammonite green nodule represents an exceptional example of Jurassic preservation, combining two large ammonites within a single natural nodule. Specimens of this size and composition are increasingly scarce from the Jurassic Coast. It is ideal for serious fossil collectors, museums, educational institutions, or statement interior display. The inclusion of a hand-signed Premium Certificate of Authenticity further elevates this specimen as a high-grade collectible. Each fossil we offer is individually selected to ensure you receive an authentic, visually striking, and scientifically meaningful piece of Early Jurassic marine history from one of the world’s most important fossil localities.