I still occasionally confuse these two groups of invertebrates, but the key distinction lies in their shell symmetry. In bivalves, the two valves (shell halves) are mirror images of one another, whereas in brachiopods, the valves are dissimilar. Conversely, a single brachiopod valve is symmetrical along its midline, while an individual bivalve valve is asymmetrical.
Most of the bivalves and brachiopods encountered on the Folkestone foreshore consist of a single valve, though complete pairs are sometimes found. Nodules containing multiple specimens also occur. Fossils are commonly preserved in black phosphate or in dark red with pyrite. I generally do not recommend collecting pyritized specimens unless they are particularly rare, as they are highly susceptible to pyrite decay (also known as “pyrite rot”), which can spread to other fossils and eventually reduce them to dust.
Some specimens can be recovered directly from the clay, where they may retain a striking iridescent shell. However, these are extremely fragile and require specialized preparation and conservation techniques. Without proper treatment, such fossils are prone to breakage, decay, or loss of their luster. For this reason, I would not advise collecting clay-preserved examples unless you are experienced in fossil preparation and preservation.
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On this page you will find some of the better examples in my collection currently. There are many different species to be found at Folkestone. For a better catalogue I recommend a copy of "Fossils of the Gault Clay"
Actinoceramus subsulcatus
(Wiltshire, 1869)
A very strange looking bivalve. As you can clearly see the shell is almost half and half in design. Showing horizontal and well as vertical ridging. Not often seen.
Find frequency on the foreshore: Rare
Euthymipecten beaveri
(Dhondt & Dieni 1988)
A hard to find bivalve. Only one I have discovered, fully phosphatized and robust. You can see the 3 holes towards the bottom. Most likely predentation from a predatory gastropod, maybe Gyrodes gentii.
Find frequency on the foreshore: Very rare
Limaria gaultina
(Woods)
Another rare bivalve, easily missed due to its small size. Largest example I have is 2.5cm long.
The above example is very nice as it has both test sides included in the nodule.
Find frequency on the foreshore: Rare
Actinoceramus salomoni ?
(d'Orbigny)
This is a very worn bivalve, I only tentatively pass an ID on this. If incorrect please inform me and I will amend.
Find frequency on the foreshore: Rare
Birostrina sulcata
(Parkinson)
Probably the most common bivalve to be found at Folkestone, I have never not seen one.
Almost always devoid of the test and showing the phosphate internal mold. A robust and easy to spot fossil.
I have found them from as small as 1cm all the way to a rare 8cm.
Find frequency on the foreshore: Rare
Plicatula gurgitis
(Pictet & Roux)
Unfortunately this is a very worn example, a fresh specimen from the clay shows high ornamentation.
Find frequency on the foreshore: Rare
Panopea mandibula
(J. Sowerby)
An extremely rare bivalve, from the Lower Greensand. Easy to spot due to its size at almost 6cm long.
This example although cased in black phosphate still shows original test.
Find frequency on the foreshore: Rare
Linotrigonia fittoni
(Deshayes)
The above example is an incredibly rare bivalve. Only found in Bed I (Junction beds) of Folkestone.
I found this after stormy weather broken off from some greensand boulders.
Find frequency on the foreshore: Very rare
Pectinucula pectinata
(J. Sowerby)
A nice example of this common bivalve, this one still has its test attached as it was freshly washed out.
Normally these are found devoid of any test leaving just the internal black phosphate mold that you can see in the bottom left.
Find frequency on the foreshore: Common
