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Introduction
Aust is a specialist fossil collecting location that requires some previous collecting experience to fully appreciate. The abundance of fossils is limited to recent cliff falls, as the site is regularly picked over by experts. During our recent visit in September - which followed a period of heavy rain - there were no new exposures. However, it was possible to find a number of bone fragments from other visitors' discarded material!
Local information boards click here to enlarge
Visitors can also familiarise themselves with the local geology using the information boards located at the southern entrance (see above).
Where to look for fossils?
The cliffs at Aust are most famous for the Rhaetian exposures - visible as the grey layer located immediately above the red coloured Mercia Mudstone. From this thin horizon comes an abundance of bones and marine reptile remains. Unfortunately this layer is located about 8 meters up the cliff face, so collecting is reliant on material that has fallen on to the beach.
The Westbury Formation (Rhaetic beds) is located immediately above the red coloured Mercia Mudstone group.
Searching
within the foreshore it's possible to find numerous
Keep an eye out for suspect rocks - distinguished by their orange outer surface - which occurs due to the iron rich sediment rusting once exposed to the air and water on the foreshore. Of course, once you've familiarised yourself with the content of these boulders, it's possible to find fresh fragments that have not yet rusted.
It's possible to find fossils on both the north and south sides of the Severn Bridge, however in recent months the greatest erosion was evident to the south. It's possible to walk beneath the bridge via a small connecting path.
What fossils might you find?
During our afternoon at Aust the fossils found were limited to a number of small bone fragments, shells and fish scales. It was evident that with fresh exposures, Aust could yield some potentially excellent specimens.
All of the fossils pictured above were found to the south of the Severn Bridge. There were no recent exposures on the northern side of the bridge.
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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