The low cliffs and rock platforms along the coast from the mouth of the River Ogwr south east towards Dunraven Bay (Southerndown) provide outstanding access to some of Wales' geological heritage.
Most of the rocky outcrops around the high tide mark are of Carboniferous Limestone (about 335 million years old).
In the area around Grid Reference 865-746, both on the wave-washed platform and on horizontal bedding planes capping the low cliffs, it is possible to see large curved solitary corals, colonial corals and large brachiopod shells.
Wales was situated close to the Equator at the time, under a monsoonal-type of climate, with warm, shallow tropical seas. Within some 15 million years the seas had closed and a mountain chain up to 4000m high (the height of the Atlas Mountains in Morocco) was beginning to form over what is now Devon and Cornwall.
In front of this developing mountain chain a basin formed in south Wales that became filled with the debris as the mountains were eroded. The river and delta deposits filling this basin became the host for Wales' coal wealth.
Eventually the forces building the mountains to the south also deformed and uplifted the coal basin. In places like Ogmore the once deeply buried (several kilometres) Carboniferous Limestone was now exposed to weathering and erosion.
By about 205 million years ago late Triassic) South Wales was an arid region at the latitudes of today's desert belts.
Ogmore-by-Sea was located on the northern edge of a dry lake basin similar to Death Valley today. At times a salt lake filled the area between Ogmore and the Mendips. The products of limited weathering in this arid setting were washed down by flash floods and their remains can be seen along the rocky shoreline with masses of fragmented limestones usually set in a white of red matrix.
There are even small valleys (wadis) cut into the Carboniferous Limestone, filled by these deposits, clearly visible again near 865-756. By about 200 million years ago (early Jurassic) the climate had changed and the seas were rising. The low hills over the present day Vale of Glamorgan were inundated to form a small archipelago set in a tropical sea. The hills were largely made of the exhumed Carboniferous Limestone.
The Ogmore-Ewenny area was one of those islands, and as the seas flooded the area, the hill was surrounded by a rocky-sandy shoreline just like it is today, only warmer, with the sea alive with ammonites and giant marine reptiles.
At Pant-y-Slade (872-741) the Jurassic shoreline sands (shelly sands full of broken molluscs) are banked against the highly irregular cliffs of Carboniferous Limestone. Telling these two limestones apart is not easy but if you look carefully the contact is marked by large coral colonies of Jurassic age, buried by Jurassic shelly sands with pebbles of darker Carboniferous Limestone.
Rocky shorelines are places of erosion where delicate features are readily destroyed; the Jurassic rocky shoreline at Pant-y-Slade is one of the finest examples anywhere in the world.
From this location look south east towards Witches Point in Dunraven Bay (Southerndown). The main cliffs are of the Jurassic Blue Lias and represent the muddy, deeper water offshore deposits around the archipelago.
Accessibility: The coastal path is probably accessible to a wheelchair but not the actual fossil sites. All the above are accessible at high tides - but of course anyone visiting any part of the south Wales coast must be aware of the dangers our local extreme tides present. The sites are all adjacent to cliffs and at Pant-y-Slade there can be a danger from large waves.
Facilities: There is a very large car park at Ogmore.
Look out for Iolo Williams as he visits the area in a TV series about The Natural History of Wales.
Professor Paul Wright is from the Department of Earth, Ocean and Planetary Sciences at Cardiff University. See the departmental website for more about its work.
The BBC is not responsible for the content of external websites
ALSO ON BBC.CO.UK:
your comments
Bill Kincaid, Chatham, Kent
I was stationed at RAF St Athan from 1971 to 1979 - used the beach all the time at Southerndown, and the 3 Golden Cups. Who remembers Glynn the landlord? Glorious days whatever the weather. As a single man or later as a married man with children it always kept us occupied - the beach, that is.
Beth Wardle, Tonyrefail
Ogmore and Southerdown are fantastic places to visit. I love the walks, especially in the summer evenings as everyone is down there doing the same thing. The horse riding is great and there are loads of places to explore. You don't need arcades near beaches to have a good time.
Eira, Watford
If the weather was better it would be the best kept secret place ever. I grew up in Wales and missed it so much when I moved away.
Sean Barlow Glyncoch
I love Ogmore.It must be the best place going.We went before with the school for a week and it was just soo much fun we even walked to Trecco bay before from Ogmore. It was so fun. I would love to go to Ogmore again.
Emma, Pontypridd
I love Ogmore. It must be the best place going. I love going there - I remember once I went with the school some time back and it was just so much fun.
Susan Heaton Wright, Hertfordshire
My grandma used to live in one of the houses in Craig-yr-eos Road and we would spend a lot of our summer holidays there. I also remember Hardees Cafe: the red and cream version and the re-built brick version. The church, where grandma worshipped; Hardees bay (directly below Hardees Cafe) and of course Tusker Rock. I used to fantasise that I could swim there and back in a day. Seeing the Somerset and Devon coast across the Bristol Channel on a clear day was wonderful, and does anyone remember the foghorn from Nash Point? We walked on the downs to Southerndown, explored the caves and rocks and watched the sunsets. A wonderful, wonderful memory.
Kevin Winterburn, Rhondda
Ogmore and Southerndown make me feel that I belong and that I feel contented when I'm there. I come here to go fishing, but personally I can just sit on the rocks and soak in the scenery. I really feel lucky that I can visit so regularly.
Mark Grabham
Me and my family visit Ogmore at least once a week. We enjoy taking our camping cooker and making hotdogs and sometimes a cooked breakfast, and admiring the beautiful scenery. Best place to be.
Bethan Wiltshire from Newport
I went to Ogmore while my mum and dad went walking the dogs. I went horse riding and I was riding the perfect little pony called Conker - he cantered along the beach and galloped along the mountains, and we walked through the estuary. I hired him to go out around Ogmore around 18 times.
Mike Clare, Hayscastle, west Wales
I sat by the ruins of Ogmore Castle on a bright beautiful morning and watched the flood of a spring tide slowly fill the car park, to see fish swim where a few hours later people would park thier cars was a little difficult to comprehend. I have since spent many a day in Ogmore, horse riding, walking the dogs and having tea and Mrs Williams' homemade cake at the farm. A truly wonderful place. I will be visiting again soon.
John from north London
Having recently been forced to take a job near Ogmore-by-sea I found very soon that I was cycling down to the beach every afternoon and have fallen in love with it. I am now back in London desperately trying to get my wife and family to move there.
Arthur Bartholomew, Manhattan Beach, California, USA
Yes, Southerdown is magical, friends of mine, Keith and Jenni Roberts ran the 3 Golden Cups in the early 90's and my wife and son visited with them. My son was only about two and we had a wonderfully relaxing time, difficult to duplicate in the states. Now he is 21 and a tatooed punk rocker - time does fly by!
Eddie Gilbertson, Melbourne, Australia
I can remember visiting Ogmore every day when I lived in south Wales. My mother who was in her 80s loved to watch the ships from the top of the cliff and we would stay there for hours just looking out to sea. Just after the second world war, mum and dad spent most of their day riding on their motor bike and sidecar down to Ogmore.
Peter Beales From Ogmore-By-Sea
I am very lucky to live here, I fell in love with the place some 25 years ago and knew I had to live here.I placed an old chest full of coins and cheap costume jewellery in one of the caves for my daughter to find,a priceless memory for me. It is truly enchanting, and the Host for the OGfest 2008 music festival in July 25th 26th and 27th for the youngsters of Bridgend, all proceeds to go to Ty-Hafen childrens hospice.
Said Ahouiyek, London
On a day trip went to Ogmore-by-Sea and drove past some beautiful South Wales scenery. Being a former Geography teacher I found the topographical potential here fascinating; a river delta, sand dunes, exposed peninsula and much more to study. Besides, living in London I need a trip to places like this every now and then to refocus from the bustle of London. The wind and cold were driving (March '08)but it was well worth the experience. Would like to go to the Pembroke coast next!
John Smith, Sunderland
Having made a delivery to the Ford plant, I decided to follow the signs for Ogmore-by-sea. As I drove through the village I was greeted by the most beautiful shoreline scenery. I parked at the top of a hill, and walked down the embankment and looked out to the coastline off toward Southerndown. The views were spectacular and i just sat on the rocks watching a few lads fishing, and just taking it all in. It is an awe inspiring place to visit, and will be visiting again and again and again. A very natural beautiful place.
Jason Thompson, Bridgend
I moved here with my wife and son 2 1/2 years ago and immediately found Southerndown and Ogmore. We spent nearly every day of that summer after work on one of these two lovely beaches. This summer we have added to the family with a little girl and she loves it too!
Huw Thomas from Eastbourne
I spent my formative years in Ogmore-by-Sea, originally living on the caravan site from the age of seven and then living in a bungalow on the seafront, until moving to London fifteen years later. When we lived on the caravan site my mum would take me with her to shop at Hardey's cafe, where Mrs Edwards performed mesmerising price additions on the laid out sheets of brown paper wrapping. For me that stretch of coastline is a magical place and will always feel like 'home'.
Alex from Plymouth
The best time in my childhood was spent living in Southerndown, lots of adventure, the mystique in and around the ruins, the beach with its small sometimes tiny treasures. A dreamy place.
Frank Perretta, London
I was evacuated with my brother and sister to Southerndown during the war. Attended school at St Brides Major - beautiful place, had the complete run of deserted beaches. Lived at Ogmore-By-Sea after the war - remember Hardees Cafe. We still talk about those lovely days.
Kim Beaven from Barnet.
I spent all of my childhood holidays in Ogmore, my grand parents lived down the Craig-yr-eos Road. As you pass the Pelican to get there it was like going into a different world ... a shangri-la as my dad puts it. A piece of heaven in my heart forever.
Allan and Rachel Cornhill from Brackla
We have recently moved from Newport to Brackla and have found Ogmore Beach. What a wonderful place. Being South Africans we feel at home, walking on the beach with our dogs. Just a pity people leave all their litter lying around and don't appreciate the beauty of nature. Otherwise a wonderful place.
Tom Jenkins - Cowbridge
A wonderful area, but may I reccomend the ever growing Three Golden Cups pub, a fantastic building with great staff, service and well cooked food. A true joy that eclipses the area that is Southerndown.
Maxine Peebles, Newport
One of my many favourite childhood places. Always remember the rock pools and the caves - I now take my daughter there who loves it. Still many years to spend down at Southerndown and lookin forward to them very much.
Ceri, Barry
I spent every day every summer down Dunraven Bay when I was growing up in the local village. The private beach is lovely and the place has lots of history and a great ghost story - the Blue Lady. Loved it, miss the place, have it as my screen saver, good memories.
Joanne Powell, Rhydyfelin, Pontypridd
I absolutly love Ogmore, I think it must be my favourite place on earth. I visit it as often as I can and have just intoduced a friend to area who has lived in Pontypridd for 40 years and has never been!! Of which I might add, is now hooked! I've been there alone and with my family and have spent many happy hours with my children who inform me they have lots of happy memories of rock climbing, walking, making sandcastles and swimming in the sea. I have a special place in my heart for Ogmore which I'll always treasure.
Clive, Ogmore
I grew up in Tuskar House,Ogmore by Sea in the 40's and 50's. I've got wonderful memories of playing 'cowboys' in the quarry, exploring caves and swimming in the beautiful sea. Hardees cafe was situated on the main road, it was made of corrugated iron painted cream on the sides and red on the roof, inside it was all wood. Ogmore is a magical place and I've been lucky enough to be able to move back here - a little piece of heaven on earth!
Terry Morgan from Blackwood
In the fifties, most weekends, my parents were able to drive my brother and myself to Ogmore. Our mother (Nancy Owen) was born there in 1906 - there were only three houses on the front then. I always remember her telling us on the way home that she felt so much better having breathed the fresh air there. Now I am 60 years old, and after visiting there, I fully understand at last!
Bev Arscott nee Fletcher, Forest of Dean
My grandparents lived at Bryncethin and so I spent all my summers in Wales - I used to catch a bus to Ogmore and Southerndown and spend my days clambering over the rocks and paddling. This year I was able to introduce my niece and my great niece to the wonderful experience that is the beach and landscape at Ogmore by sea and Southerndown. It has changed a little - the bus stop was at Hardies cafe which I could not find but generally it was the same and magical!
Emmajane, Pencoed
I remember going to Ogmore-by-sea as a child and loving it. After moving to Bristol I used to drive over most weekends to go to Ogmore, then I settled in Pencoed and still we end up in Ogmore almost every other day. You can get quite hooked on it ... it's fab.
Jenny from Cardiff, originally Bridgend
My father is from Southerndown and I lived there for a few years before moving to Sarn, but always spent holidays with my grandparents in Westfield (across the road from the Three Golden Cups). I haven't been to Southerndown for a long time now as I know it has changed so much from when I was a girl. I intend to go back one day though.
Janice Shipp, Barnet, Hertfortdshire
I've just been back to Southerndown for the first time in years. I grew up in Cardiff and visited regularly till my parents died a few years ago. I have always missed the beaches around Cardiff, and have recently missed coming down to Wales, so came down for a few days and brought my children along. If anything, it turned out to be better than I remembered it and now I want to make sure I come back regularly.
Zara de Candole from Surrey
We have just returned from a week long holiday renting a bungalow on the beach at Ogmore. Truly wonderful for adults and children. Superb beaches, horse riding, the fabulous stepping stones over the river leading to a tiny, secret tea room - heaven! We will be back...
Emma Standen from Cardiff
I went to Ogmore and Southerndown on a school trip and it was lovely. I had the time of my life walking through all the caves even though I was scared. I am hoping that when I take my family the weather will be nicer and the tide will be out so I can take them in all the caves.
Matt, ex-Ogmorian
Ogmore is a beautiful place. When you live there, it is easy to take it for granted. When you move to a city or town you appriciate it all so much more. Aber-ogwr - a beautiful place with some of the best sunsets I've ever seen.
Sarah from Bridgend - now St Cloud, Florida, USA
If I am feeling homesick then I look around the Southerndown beach is all it takes.. I loved my summers here. The Three Golden Cups pub at the top of the beach is a pleasant place to sit and have a meal with family or friends.
Brian Robinson, Kingston upon Hull
Having had my childhood there I think it is the most wonderful place ever, having been to many countries. Would love to go back but housing is too expensive.
Carol Backhouse, Cardiff
I was born in England but have spent 40 years in either Bridgend or Cardiff. My children and I have spent many happy hours at Ogmore. I now take my grandchildren and have wonderful times with them.
Gwyneth Jones from Ogmore-by-Sea
My husband and I built our house here in 2000 overlooking the car-park. We would love to find a photo of the Cafe which stood on this site years ago.Was this hardee's Cafe, mentioned above? I came to the beach many times from Cardiff, when I was a small child (in the fifties)and remember visiting the cafe. Can anyone oblige?
Reg & Christine Crosby, Spain
We lived in Ogmore-by-Sea for some 16 years before retiring to Spain, we left many friends and memories there. Sitting and watching the every changing moods of the sky & sea. Walking on the beachs & fossil hunting in Southerndown Bay. We love to return when we are in the UK.
rita tait from Hay-on-Wye ( formerly Bridgend!)
my children's late uncle used to say that when he was a POW on Crete WW2 he kept sane by conjuring up a mental picture of the estuary at Ogmore & praying that he would get to see it again. He was in his early 20s but that was what kept him sane for Black Mts here is very lovely.)
Chris Pearce-Webb, Chepstow
We discovered Ogmore and Southerndown by accident whilst driving around. Dunraven Castle was an Alladin's cave for our kids and the rock pools are fantastic keeping them entertained for hours.
The jurrasic cliffs to the east of the Castle are breathtaking. An ice cream before we made for home made us one happy family.
Toby Dobson from Cowbridge
My nan has a bungalow in Ogmore on the seafront and I have been goin there since I was a baby. I go there practically all the time. I always remember goin there when I was little in the summer exploring the caves on the beach. Every weekend we take my dog to Merthyr Mawr for a walk all the way down to the seafront.
Jan Butler (nee Youlten) Ottawa, Canada
I grew up in Bridgend and after school visited Ogmore and Southerndown frequently. It was and still is so very memorable for me. I miss the ocean so much now living in Canada. I came back this past May '05 on my 50th birthday re-visiting my roots and felt totally at home with the sheep roaming the cliffs, seeing the rock pools and crabs, caves and area, how I remember it - just wonderful. Can't wait to come back again.
Louise frm Bridgend now living in Adelaide Austral
No beach in the world can beat Ogmore and Southerndown, so much character & history -great childhood memories of climbing the rocks and exploring the caves.
I can't wait to visit next year!
Amanda Mohabir, Cross Inn
I go to Ogmore a lot whatever the weather. Climbing over the rocks is great fun and when the sea is out the sandy beach is beautiful. There are even castle ruins to explore.
Caitlin Newham, Llwynrhyddid
Tusker Rocks seem very fascinating!
I would love 2 actually walk on them!!!
Tusker Rocks seems like a BEAUTIFUL place
Tony Edwards Wattsville,Crosskeys.
Ogmore is a fantastic enchanted place to be. I found that 'something special' many years ago while visiting my grandfather's wooden bungalow.As a youngster my best fun was going out to Tusker Rock in my canoe with some local boys and walking around.
I love coming back. Hardee's Cafe is long gone, and the bungalow like the caravan site, probably won't be long now.
Barbara Carr from Cambridge,Ontario Canada
Originally from Merthyr Tydfil ,but lived in Bridgend for a few years,my husband and I love Ogmore By Sea we just love to go and sit on the rocks and watch the tide come in and just enjoy the view of the dunes and walk along the sea.
Philip Gibbs, Fleur-de-Lis
Southerndown is a great place to take the kids. Try looking for devil's toenails (small shellfish fossils) among the rocks on the beach. They soon become engrossed.
John Hopkins, St Catharines, Canada
Ogmore-by-Sea, Southerndown and Merthyr Mawr were favourite Saturday family outings as a child in the '50s (I think because there was no fairground). Dunraven Castle was still in use as a hotel and we used to dig for fossils in the cliff. The cliff walks were rather congested in those days. Wonderful memories brought back.
lowri pritchard from bridgend
I love dunraven bay, i surf there wenever I can! It's not that well known but I like beaches that are more isolated and not necessarliy that popular. I'm 13 and I aspire to bring my children there in the future.
David Williams from Nelson
Ogmore is one of my favourite places. Inspiring and the pub is excellent!
Frank O Donoghue , Ireland
Absolutely fab place I pray for sunny days so I can go to ogmore and chill out in the wonderful peace and quiet. Oceans of space and great if u like rocks. One of my favourite places in Wales
Andy Thomas, Cowbridge
We have to go there for geology trips, its grand!!!!!
Don Miller, Shenzhen, China
The beach at Rest Bay is so flat - the tide goes out forever - and the wind blows hard all the time. Now I see some logic to it, rather than a malignant deity.
Delia Morris,Ystrad Mynach
I have been to many places around the country but none have ever made me feel quite like Ogmore, Ssoutherndown, Rest Bay. The feeling of wanting to be part of a place is overwhelming, also the feeling of exileration and completeness is extraordinary since going to these places has now triggered something in me to take up coastal walking on a much greater scale.
Angela Kerslake, Aberdare.
One of my many childhood memories is visiting Ogmore + as an adult it is a special place for me with so many lovely memories. It's like being transported back to when I was a little girl again, having hours of fun searching the rock pools for crabs + not having a care in the world. Lovely place.
