The multi-coloured cliff faces between Penarth and Barry are the consequence of rock deposition in varying environmental conditions. The bright red rocks testify to the arid desert that prevailed during the Permian and Triassic periods.
These mudstones were laid down in a temporary lake on the edge of the desert. As the sea rose, the lake filled and changed to a lagoon and the deposited rocks become a yellowy green colour. Gradually the rocks turn black, as the lagoon completely fills with salt water.
The youngest rocks, known as Blue Lias limestone, were deposited in a marine environment during the Triassic and Jurassic.
Within the Blue Lias boulders or rock platforms along the beach (away from the cliff faces for safety) you might be fortunate enough to find fossil vertebrae of extinct marine reptiles such as ichthyosaurs and plesiosaurs.
Ichthyosaurs resembled dolphins in shape and possibly lifestyle. Plesiosaurs were the largest marine reptiles living at the time and grew to 14 metres long. They both ate fish, belemnites and ammonites, and fossils of these sea creatures are also preserved within the Blue Lias rocks. The 'bone beds' near Lavernock Point contain fish and reptile teeth, scales and bones, plus coprolites - fossilised dung!
Access: from Penarth (ST185704), Lavernock Point (ST186681) and St Mary's Well Bay (ST176674). Check tide times, especially between Lavernock Point and St Mary's Well Bay, to avoid getting cut off.
Facilities: Refreshments, toilets and parking available at Cliff Parade, Penarth. There is limited parking by the church at Lavernock Point, and summer parking at St Mary's Well Bay (roadside parking only during the winter).
Fossil vertebras of these marine reptiles have also been found at Nash Point, near Llantwit Major (SS916800); parking for a small fee, refreshments and toilet facilities are available. Look out for Iolo Williams (left) as he visits the area in a TV series about The Natural History of Wales.
For more information, see the Geological Walks in Wales leaflets for 30p available from:
South Wales Geologists Association
c/o Department of Geology
National Museum & Gallery Cardiff
Cathays Park
Cardiff CF10 3NP
Phone 029 2057 3213
Email geology@nmgw.ac.uk
See the South Wales Geologists Association website for more about geology.
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your comments
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Ian from Cardiff
Does anybody have any info on any old military installations that may still be or were at Lavernock Point?
Mon Feb 16 13:57:06 2009
Shakira Clare from Daventry
I think this walk is great so that you can go and see the sea or have a picnic while you're there.
Tue Feb 13 14:49:41 2007
Sheryl Evans
A fantastic and interesting place to visit. Not just in a geological sense but Lavernock Point also has a great scientific history. Marconi gave his first wireles transmission over water to Lavernock Point from Flat Holm, in the Bristol Channel in 1897.
Tue Aug 29 10:18:48 2006
Tau Ceti - Cardiff
I've been searching for fossils all the way quite often down that way; only ONCE I found half an ammonite!! I did see lots of fish bones - the Lavernock fishbeds - but so far none worth taking either because fo too small size, or too large a rock to transport!
Wonderfulplace anyway, favourite spot Iron age fort on Sully Island....
Mon Jan 23 15:55:00 2006
sharon from pontypridd
i found some fantastic fossils in llantwit major a few years ago its a fantastic place to go for afternoon take a flask and enjoy
Thu Dec 8 19:21:28 2005
Eli Kemp from Cardiff
I think this walk is great. My and my geology class came down for a field trip. It was amazing -the fossils I found were fantastic. i recommend it!
Mon Oct 31 15:14:22 2005
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