Fossils for Sale - High-quality BRITISH and WORLDWIDE Fossils. An impressive selection of fossils, including Ammonites, Trilobites, Belemnites, Fossil Fish, Fossil Shark Teeth, Fossilised Insects in Amber, Dinosaurs, and Reptiles. UK Fossils was formed in 1988 and collects and preps our own fossils in the heart of the Jurassic Coast, collecting fossils from Lyme Regis, Charmouth and Somerset. Our passion for fossils is reflected in our carefully curated collection, which includes some of the rarest and most unique specimens available.

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Amaltheus Ammonite Fossil Jurassic Yorkshire UK Genuine Specimen with Certificate of Authenticity

Amaltheus Ammonite Fossil Jurassic Yorkshire UK Genuine Specimen with Certificate of Authenticity

Original price was: £22.80.Current price is: £18.24.

All of our Fossils are 100% Genuine Specimens & come with a Certificate of Authenticity

**Please note: Some fossils maybe propped up for photo purposes**

Name: Dactylioceras commune

Specimen: Ammonite

Age: Jurassic

Location: Yorkshire, UK

Size (picture scale cube=1cm):   77 x 28 x 58mm (3.03 x 1.1 x 2.28 inches)

Grade B: Display quality

Dactylioceras was a widespread genus of ammonites from the Lower Jurassic period, approximately 180 million years ago.

Ammonites are one of the most recognisable fossils around, this is due to their familiar spiral shape shell, reminiscent of what we know as a snail shell, though these creatures are not related to snails at all. They were marine animals, present between 240 – 65 million years ago, who had a coiled external shell similar to that of the modern nautilus, and although they resembled a modern day nautilus, these molluscs are more closely related to living coleoids i.e. octopuses, squid, and cuttlefish.

 

ACTUAL AS SEEN: The image shows the EXACT specimen you will receive. The specimen has been carefully hand selected and photographed. Measurements are as accurate as possible, though be aware measuring precise dimensions can be difficult from irregular shaped items. Whilst we portray colours as close to life-like as we can, colours will vary if taken in sunlight, indoors, from monitor to monitor and device to device. Once this specimen is sold, we will update this listing with new similar selected item, with a new photo and dimensions.

 

What is a fossil?

The word Fossil used to be defined as ‘something dug up’. Now-a-days it generally means ‘The remains or trace evidence of prehistoric life’. The study of fossils is called palaeontology; someone who collects and studies them is called a palaeontologists. Fossils can be as tiny as a grain of pollen or a seed for e.g. or as huge as a limb bone from a giant dinosaur. For animal or plant remains to have become ‘fossilised ‘, they must go through a certain process that preserves them for up to millions of years after they have died. Usually it is only the hard parts of plants and animals that survive this long process.

How Fossils Formed

 

The most common method of how fossils formed is once an animal or plant dies it falls to the ground, then is covered by sediment. This is often sediments brought from water. In the diagram above, the Ammonite died in a river, and sediments over time covered the ammonite (shown in the second diagram). Finally after hundreds of thousands, or millions of years, the land is eroded and the fossil can be seen.

Of the vast amount of prehistoric life that died, it is only a tiny amount that has survived the fossilisation process. The conditions when the majority of life died were just not right at that time to preserve them. Most fossils are found in sedimentary rocks which were formed from the sediments of rivers, lakes and seas. The majority of the animal and plant fossils we find today had originally died near these areas, got broken up and deposited on the beds of the rivers, lakes and seas. The sediments covered them and over time some of the layers grew so thick that many of them got crushed. The sediments compacted and over time and turned to rock. The rocks shifted, moved and became exposed to the elements. This process can take up to several hundred million years. Now as the rocks erode or are quarried for example, the fossils become exposed and can be collected.

The Best conditions for Fossilisation

1. The quick burial of animal remains in moist sediments. This prevents scavengers from eating and bacteria from decaying them.

2. The quick burial in volcanic ash. Many dinosaur bones in the American west have been found buried in volcanic ash.

3. The presence of hard body or plant parts, teeth, bones, shell and wood for example.

4. Unchanging temperature conditions.

5. Ground water that is heavily mineralised.

6. Sediments that are very fine make a better burial than coarser gravels.

7. Calm conditions, so that remains are not broken up (by wave or currant action for example)

(Actual as seen)

Only 1 left in stock

SKU: FP9756 Category:

Description

Amaltheus Ammonite Fossil – Jurassic, Yorkshire, UK

This genuine Amaltheus ammonite fossil comes from the world-renowned Jurassic deposits of Yorkshire, United Kingdom. A carefully chosen specimen, the photograph shows the exact fossil you will receive. Full sizing please see photo for precise measurements and scale. Every specimen includes a Certificate of Authenticity lifetime guarantee generic card, confirming its natural origin and geological age.

Yorkshire’s coastline, particularly around Whitby and the Cleveland Basin, is internationally famous for producing exceptional Lower Jurassic ammonites. Amaltheus is one of the most recognisable and scientifically significant genera from these deposits, making this fossil both a striking display piece and an important example of Britain’s Jurassic marine life.

Geological Age and Stratigraphy

Amaltheus is characteristic of the Lower Jurassic, specifically the Pliensbachian Stage, approximately 190–183 million years ago. In Yorkshire, it is commonly associated with the Amaltheus margaritatus Biozone within the Marlstone Rock and related marine sedimentary formations. These strata were deposited in a shallow epicontinental sea that once covered much of northern England.

The fine-grained mudstones and iron-rich sediments of this environment provided excellent conditions for fossil preservation. Rapid burial beneath marine sediments protected shells from scavenging and physical damage, allowing intricate details to survive for nearly 200 million years.

Fossil Type and Preservation

This specimen represents a true body fossil of an extinct marine cephalopod. Amaltheus possessed a robust, planispirally coiled shell composed originally of aragonite. Over geological time, mineral replacement and compaction preserved the shell structure within the surrounding rock matrix.

Typical features of Amaltheus ammonites include:

  • A compressed, discoidal shell form

  • Strong, pronounced ribbing radiating across the whorls

  • A distinctive sharp ventral keel running along the outer rim

  • Clearly defined whorl sections with visible growth lines

The keel and rib structure likely improved hydrodynamics, allowing the animal to move efficiently through Jurassic seas. These morphological traits make Amaltheus easily identifiable and highly desirable among collectors.

Taxonomy and Scientific Significance

Amaltheus belongs to:

  • Class: Cephalopoda

  • Subclass: Ammonoidea

  • Order: Ammonitida

  • Superfamily: Eoderoceratoidea

  • Family: Amaltheidae

The genus Amaltheus was formally described in the early 19th century and has since played an important role in Jurassic biostratigraphy. Due to its relatively short stratigraphic range and distinctive morphology, it serves as an important index fossil for correlating Lower Jurassic rock layers across Europe.

Ammonites such as Amaltheus were active marine predators or opportunistic feeders, related to modern squid and cuttlefish but protected by an external chambered shell. The internal chambers were separated by septa and connected by a siphuncle, enabling buoyancy control as the animal moved vertically within the water column.

Depositional Environment

During the Pliensbachian Stage, Yorkshire lay beneath warm, shallow seas rich in marine life. Periodic low-oxygen bottom conditions reduced biological disturbance, aiding fossil preservation. Sediments accumulated slowly, entombing shells within mud that would later lithify into shale and marlstone. These calm marine conditions are responsible for the remarkable clarity and definition often seen in Yorkshire ammonites.

Authenticity and Display

This Amaltheus ammonite fossil is a genuine specimen from Yorkshire, UK. It has been carefully selected for quality and presentation value. The image provided shows the actual fossil you will receive. Full sizing please refer to the photo.

Each fossil includes a Certificate of Authenticity lifetime guarantee generic card, ensuring confidence in its authenticity and geological provenance.

An outstanding example of a classic British Jurassic ammonite, this Amaltheus fossil is ideal for collectors, geology enthusiasts, educational study, or as a distinctive natural history display piece.

Additional information

Weight 10 g
Era

Jurassic
Origin

United Kingdom

Jurassic Information

The Jurassic Period (201–145 million years ago) was the golden age of dinosaurs, with iconic species like Brachiosaurus, Stegosaurus, and Allosaurus dominating the land. It was a time of warm, humid climates, with high sea levels that created vast shallow seas, supporting abundant marine reptiles, ammonites, and early coral reefs. The first birds, such as Archaeopteryx, evolved from small theropod dinosaurs, while early mammals remained small and nocturnal. Lush forests of cycads, conifers, and ferns covered the land, providing food for giant herbivores. The breakup of the supercontinent Pangaea accelerated, shaping Earth's geography and setting the stage for the diverse ecosystems of the Cretaceous.

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