Description
Genuine Winchellia Ammonite Fossil
This genuine ammonite fossil is identified as Winchellia sp. and comes from Sherborne in Dorset, United Kingdom. It is preserved from the Inferior Oolite Group and dates to the Lower Bajocian laeviscula Zone of the Middle Jurassic. The photographs show the actual carefully chosen fossil offered for sale, so the ammonite pictured is the exact specimen you will receive.
Lower Bajocian Middle Jurassic Age
The Bajocian is a stage of the Middle Jurassic Period, spanning approximately 170 to 168 million years ago. This specimen comes from the earlier part of that interval and is more precisely assigned to the laeviscula Zone. During the Bajocian, warm shallow seas covered parts of southern Britain and supported ammonites, bivalves, gastropods, brachiopods, echinoids, and many other marine organisms.
After death, an ammonite shell could settle onto the seabed and become buried by carbonate-rich sediment. Compaction, mineral replacement, and later geological change preserved the shell or internal mould as a fossil. The documented zone gives this specimen valuable stratigraphic context within the early Middle Jurassic.
Winchellia Ammonite
Winchellia was an extinct marine cephalopod with a coiled shell divided internally into chambers. The living animal occupied the final body chamber, while earlier sealed chambers assisted with buoyancy control. Ammonites were relatives of modern squid, cuttlefish, and nautiluses, although they formed their own diverse and now extinct group.
Shell shape, whorl proportions, umbilical width, ribbing, and the form of the outer edge are among the features used to compare ammonite genera and species. Winchellia specimens may show a ribbed, evolute shell with ornament that changes through growth. Examine the photographs for the coiled whorls, rib pattern, umbilical area, outer margin, natural matrix, and preserved surface details visible on this individual fossil.
Laeviscula Zone
The laeviscula Zone is an ammonite biozone within the Lower Bajocian. Biozones are intervals of rock recognised through characteristic fossil assemblages and are used by geologists to correlate sedimentary sequences. A specimen with zonal information carries more scientific context than one described only as broadly Jurassic.
Ammonites evolved relatively rapidly and were widely distributed through ancient seas. Their changing shell forms make them excellent index fossils, helping palaeontologists compare rocks from different localities and reconstruct evolutionary succession.
Inferior Oolite Group Geology
The Inferior Oolite Group is a classic British Middle Jurassic rock succession. Its name refers to oolitic limestones formed from tiny rounded carbonate grains, although the group also includes varied marine sediments. These rocks record changes in water depth, seabed conditions, sediment supply, and marine communities.
A fossil with Inferior Oolite provenance can complement a collection arranged by British rock unit, geological stage, ammonite zone, genus, or ancient marine environment. It also provides a tangible link to one of southern England’s most historically important Jurassic successions.
Sherborne Dorset Provenance
Sherborne lies in Dorset, a county internationally known for Jurassic geology and fossils. Inland exposures around the town preserve parts of the Inferior Oolite succession and have produced important ammonite assemblages. A precise locality adds geographical and educational value to this specimen.
Natural Fossil Character
Natural colour, mineral texture, small breaks, areas of wear, and variations in preservation reflect the fossil’s long geological history. These are expected features of an authentic specimen rather than manufacturing defects. Every ammonite preserves a different balance of shell material, mineral replacement, internal mould, and surrounding rock.
The multiple photographs show this exact Winchellia specimen from useful angles. They allow close inspection of its condition, ribbing, outline, matrix, proportions, and display qualities. Full sizing is shown in the photographs, which provide the clearest scale information for this individual fossil. The images are not stock photographs and do not represent a similar specimen.
Certificate of Authenticity
This genuine fossil includes a generic Certificate of Authenticity card with a lifetime guarantee. Its Lower Bajocian age, laeviscula Zone placement, Inferior Oolite context, and Sherborne provenance make it a distinctive addition to a fossil cabinet, study collection, office display, or educational setting. It is also a thoughtful gift for anyone interested in Dorset fossils, British Jurassic geology, ammonite evolution, palaeontology, or genuine natural history specimens.
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