Description
Genuine Ebrayiceras oculatum Ammonite Fossil
This carefully chosen fossil is a genuine Ebrayiceras oculatum ammonite from the Inferior Oolite Group at Burton Bradstock, Dorset, UK. It is recorded from the Middle Bathonian Stage of the Middle Jurassic, representing an extinct marine cephalopod that inhabited the warm seas covering southern Britain approximately 166 million years ago.
The photograph shows the actual fossil specimen you will receive, allowing its natural shell form, ornamentation, colouration, attached matrix and individual preservation to be examined before purchase. This is not a photograph of a representative example. Full sizing and scale information can be seen in the accompanying photograph.
Middle Bathonian Jurassic Fossil
The Bathonian Stage forms part of the Middle Jurassic and followed the Bajocian. During this interval, extensive shallow seas covered large areas of western Europe, including the region that would eventually become Dorset.
These marine environments supported diverse communities of ammonites, belemnites, brachiopods, bivalves, gastropods, echinoids and other prehistoric organisms. Ammonites were among the most successful free-swimming animals within these seas and evolved a wide variety of shell forms, ornamentation styles and coiling patterns.
Because ammonite species changed relatively rapidly through geological time and were widely distributed, their fossils are especially valuable for dating and correlating marine sedimentary rocks. Distinct ammonite assemblages allow geologists to subdivide Jurassic strata into detailed biozones and compare rock layers exposed at different localities.
Ebrayiceras Shell Form and Ornamentation
Ebrayiceras is a Middle Jurassic ammonite genus recognised by its planispirally coiled shell and distinctive ribbed ornamentation. The shell developed in a single plane around a central umbilicus, with each successive whorl increasing in size as the animal grew.
The flanks may carry prominent ribs extending outward from the umbilical region. These ribs can divide or vary in strength as they approach the outer portion of the shell, creating a naturally sculptured appearance. The spacing and curvature of the ribs may change during growth, so the inner whorls can display different ornamentation from the later body chamber.
Whorl proportions, the width of the umbilicus, ribbing style and the form of the outer shell margin are important features used when identifying ammonites. The amount of visible detail on an individual fossil depends on its growth stage, preservation, weathering and the extent to which the shell remains enclosed within its natural matrix.
The living ammonite occupied the final and largest part of the shell, known as the body chamber. Earlier portions were separated by internal walls called septa, forming a sequence of chambers collectively known as the phragmocone. These chambers contained regulated quantities of gas and liquid that helped the animal control buoyancy within the Jurassic water column.
Inferior Oolite Group Geology
The Inferior Oolite Group is a highly fossiliferous sequence of Middle Jurassic marine rocks found across parts of southern England. It includes oolitic limestones, sandy limestones, marls, iron-rich beds and condensed fossil horizons deposited under changing marine conditions.
Oolitic limestone contains small rounded carbonate grains called ooids. These formed when calcium carbonate accumulated in repeated layers around tiny shell fragments or sediment particles moving through warm, agitated seawater. The grains later settled onto the seabed, where compaction and natural cementation transformed the sediment into limestone.
Deposition within the Inferior Oolite sea was frequently affected by changing water depth, currents, erosion and variations in sediment supply. During periods of slow accumulation, shells could remain exposed on the seabed, become reworked and eventually collect within concentrated fossil-bearing horizons.
These geological processes produced the rich ammonite faunas for which the Inferior Oolite is renowned. Fossils preserved within the succession provide detailed evidence of changing marine environments and cephalopod evolution during the Middle Jurassic.
Burton Bradstock Fossil Locality
Burton Bradstock is situated on the Jurassic Coast of west Dorset, a region internationally known for its exceptional sedimentary geology and fossil record. The cliffs and nearby inland exposures preserve rocks deposited during several stages of the Jurassic Period.
The fossil-bearing strata associated with Burton Bradstock record ancient shallow-marine environments influenced by currents, changing sea levels and variable sedimentation. Ammonites recovered from these deposits offer a direct connection to the prehistoric seas that once covered Dorset.
Specimens from documented British localities are especially desirable to collectors because they combine natural aesthetic appeal with clear geological provenance. An identified Ebrayiceras oculatum from Burton Bradstock makes an interesting addition to a collection focused on Dorset fossils, Bathonian ammonites or British Jurassic palaeontology.
Scientific and Geological Details
Fossil type: Ammonite
Scientific name: Ebrayiceras oculatum
Order: Ammonitida
Geological period: Jurassic
Geological epoch: Middle Jurassic
Geological stage: Middle Bathonian
Geological unit: Inferior Oolite Group
Locality: Burton Bradstock, Dorset, United Kingdom
Ammonites belonged to the cephalopods, the same broad group of marine molluscs that includes living squid, cuttlefish, octopuses and nautiluses. Although their coiled shells resemble those of modern nautiluses, ammonites formed a separate and highly diverse evolutionary group that became extinct at the end of the Cretaceous Period.
Fossilisation and Natural Preservation
After the ammonite died, its shell settled onto the seabed or was transported by currents before burial. Sediment gradually accumulated around the shell, protecting parts of it from complete destruction. Over millions of years, mineral-rich groundwater, compaction and geological pressure transformed the sediment into rock and preserved the ammonite as a fossil.
The original shell material may have been retained, mineralised, replaced or dissolved, leaving a natural internal mould. Some specimens preserve a combination of altered shell material, sediment-filled chambers and surrounding rock matrix.
Any incomplete areas, natural fractures, surface wear, mineral-filled sections, attached matrix or colour variations are authentic geological characteristics. These features reflect the specimen’s burial, fossilisation, exposure and recovery and ensure that every genuine ammonite has its own unique appearance.
Collectable Dorset Ammonite Specimen
This Ebrayiceras oculatum ammonite fossil would make an excellent addition to a collection of British fossils, Dorset ammonites, Middle Bathonian fossils, Inferior Oolite specimens or prehistoric marine cephalopods. Its recorded identification, geological stage and locality also make it suitable for a fossil cabinet, educational collection, geological display, office or distinctive gift for a Jurassic fossil enthusiast.
This fossil is a 100% genuine specimen and includes a Certificate of Authenticity generic card with a lifetime guarantee. It has been individually selected for its collectable qualities, and the photograph shows the exact specimen that will be supplied.
Full sizing please see photo.
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