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You are currently here: Home > Fossil Locations > Isle of Wight > Alum Bay |
In partnership with JuniorGeo |
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Introduction
Alum Bay is located on the most western tip of the Isle of Wight and is an area of outstanding natural beauty, famous for its coloured sands and the chalk Needles and lighthouse. Many people flock from the mainland to view the scenery and visit the 'Needles Park' during their stay.
Ferry crossing from Southampton to Cowes
The ferry crossing takes around an hour (depending on where you depart from) and then there's a 30 minute drive from Cowes to Alum Bay.
The 'Needles Park' is a popular family attraction with tourists, providing a variety of sand based activities, including glass making, small rides and souvenir shops. You can easily spend a good couple of hours within the park before heading down to the beach, although for many reading this page, it's more likely to be the other way around!
From the 'Needles Park' there are a three routes to the beach; many people choose the chair-lift, as this saves descending the steps or dirt track. Please follow the instructions beneath the UK map above to find the dirt track. Alternatively, steps lead down to the beach from within the 'Needles Park', towards the seaward end (clearly indicated within the park).
(Left) View over the visitor chair lift towards the Needles and the lighthouse. (Right) Visitor chair-lift as viewed from the beach.
(Left) The chalk cliffs, Needles and lighthouse in silhouette. (Right) The Needles lighthouse as viewed from a local charter boat.
Although fossils are not the main attraction, the combination of fascinating geology and stunning views, make this a worthy destination for individuals and families. It's worth spending a few hours at Alum Bay and experiencing the chartered boat trip to view the Needles and lighthouse.
The geology of Alum Bay
The geology of Alum Bay tells a story of significant biological and physical change, spanning 50 million years. The northern and middle sections of the bay are comprised of Eocene sediments, deposited in a shallow, warm sea between 35-54 mya; whereas the southern end comprises towering chalk cliffs, deposited in deeper water around 80 mya.
View from a charter boat, looking back towards the southern corner of Alum Bay. Notice the vertical coloured sands of the Bracklesham Group strata.
Alum Bay is well known for its colourful sands, which are often sold in glass vessels within the 'Needles Park' and surrounding tourist shops, and also in other parts of the country too. The sands are largely derived from the Bracklesham Group, located along the middle sections of the bay. Although the sediments were originally lying horizontally, the pressure of continental movement over millions of years has resulted in localised folding, which is now evident by the vertical position of the beds.
Geological summary of Alum Bay (click here to view scene without text)
As you head south along the beach the sediments become progressively older, and consequently the fossils you find differ depending where you search. The only consistent geology occurs in the form of flint pebbles which line the foreshore; these were originally sourced from Cretaceous chalk (see Seven Sisters for evidence of flint depositing).
Where to look for fossils?
From the beach access-point, when facing out to sea, fossils can be found in both directions - south (left) and north (right). For much of the year access to the cliff base is restricted in order to protect the faces from irresponsible hammering/digging. Please observe these restrictions and remember that this is an uniquely beautiful stretch of coast, enjoyed by many. Alum Bay is the only place in the country where such a range of sand colours can be viewed in the cliffs; collecting sand is prohibited.
The best place to search for fossils is at the southern end of the bay - within the London Clay - just before the Reading Formation and chalk cliffs. At this point the clay is slumping onto the foreshore and many fossils can be found protruding its surface; it's possible to simply pluck specimens (mainly bivalve and gastropod shells) from the clay (see photo below).
(Left) Searching the toe of the London Clay on the foreshore. (Right) A bivalve, complete with both valves, within the London Clay on the foreshore.
Fossils can also be found within the chalk exposed on the foreshore (see foreshore photos below), although the volume and range of finds is limited by the concentration of fossil material and also the accessibility of these exposures. For individuals seeking a greater scientific appreciation of the geology, a close inspection of these exposures will reveal fragments of echinoids and bivalves. Unfortunately we have no photos of chalk specimens to include at this time.
Views of the chalk exposed at the southern end of Alum Bay.
During your visit to Alum Bay, it's worth spending some time searching the Barton Group of sediments, at the northern end of the bay. Shortly after you pass the chair-lift, the Barton Clay slumps onto the foreshore (see photo below).
Views of the Barton Clay exposed on the foreshore, north of the beach access.
Luci uses a small probe to lift fossils from the London Clay.
A small steel probe or similar tool will provide a useful implement for removing specimens from the foreshore clay, although many specimens are simply lying on the surface and can be collected with ease.
For more information about the features and processes controlling coastal fossil collecting locations click here.
What might you find?
The most common fossils at Alum Bay are bivalve and gastropod shells, found within the London and Barton Clay on the foreshore. Worn echinoids and brachiopods can be found within the flint, but these are rarely of a collectable quality. The following photos show a selection of specimens gather over the space of two hours.
Protecting your finds
It's important to spend some time considering the best way to protect your finds onsite, in transit, on display and in storage. Prior to your visit, consider the equipment and accessories you're likely to need, as these will differ depending on the type of rock, terrain and prevailing weather conditions.
(Left) Fossil wrapped in newspaper, ready for transport. (Right) A small compartment box containing cotton wool is ideal for separating delicate specimens.
When you discover a fossil, examine the surrounding matrix (rock) and consider how best to remove the specimen without breaking it; patience and consideration are key. The aim of extraction is to remove the specimen with some of the matrix attached, as this will provide added protection during transit and future handling; sometimes breaks are unavoidable, but with care you should be able to extract most specimens intact. In the event of breakage, carefully gather all the pieces together, as in most cases repairs can be made at a later time...continued.
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