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Author: ExGeo

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This is some additional information and pictures to support the geology walk at Porthcawl. Take a look at the descriptions under each picture to see more information

The Localities mentioned on this post relate to the map which is included in the leaflet PDF and is repeated here to make this page easier to read. For more information and descriptions of all the localities and the start point, parking etc. please see the leaflet

To download and print this walk, please open / download the PDF version here

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Locality 1 - Oxwich Head Limestone of carboniferous age
Locality 1 - details of the fossils these are brachiopods an ancient type of seashell
Locality 2 where the small fault cuts the limestone and gives these straight lines on the beach
Locality 4 the grassy area opposite the Seabank Hotel with the subarial erosion forming a limestone pavement as can be seen in more details in the picture below. The blocks are called clints and the gaps are called grykes and often get plants growing in them as they provide some shelter and often moisture at the bottom
Locality 4 limestone pavement type weathering
Locality 6 - coral fossil
Locality 6 coral fossil
Locality 11 A deep gully eroded along a fault line

•BGS Geology Viewer is a free smartphone app to view geological maps of Britain wherever you go https://www.bgs.ac.uk/technologies/apps/igeology-app/



We hope you enjoyed this short tour of Porthcawl. If you’d like to learn more about our local geology, take a look at other pages on the South Wales Geologists’ Association website: www.swga.org.uk

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This is some additional information and pictures to support the geology walk at Cribarth from Craig-y-Nos. Take a look at the descriptions under or above each picture to see more information

The Localities mentioned on this post relate to the map which is included in the leaflet PDF and is repeated here to make this page easier to read. For more information and descriptions of all the localities and the start point, parking etc. please see the leaflet

To download and print the leaflet version of this walk, please open / download the PDF version here

Open/Download
The view north from above Locality 1 looking over Craig y Nos castle towards the Old Red Sandstone of the beacons
Fossils in the wall at Locality 3



Above and below - the area of limestone pavement at Locality 4
The old tramroad at Locality 5 with the outcrop on the right hand side as seen in this picture (looking back to Locality 4. it will be on your left (the south eastern side) as you walk the trail. A close up of the Honycombe sandstone can be seen below
Nodules of chert (just below the lens cap showing the scale of the picture) above and a vein of calcite crystals in the picture below - both are at Locality 7
Quartzite blocks at the triangulation point (Locality 8) have been used in ancient times to construct a cairn or shelter. These probably came from the crags at Locality 9 just to the north of this point

BGS Geology Viewer is a free smartphone app to view geological maps of Britain wherever you go https://www.bgs.ac.uk/technologies/apps/igeology-app/



We hope you enjoyed this short tour of Cribarth from Craig-y-Nos. If you’d like to learn more about our local geology, take a look at other pages on the South Wales Geologists’ Association website: www.swga.org.uk

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This is some additional information and pictures to support the geology walk at Ogmore-by-Sea. Take a look at the descriptions under each picture to see more information

The Localities mentioned on this post relate to the map which is included in the leaflet PDF and is repeated here to make this page easier to read. For more information and descriptions of all the localities and the start point, parking etc. please see the leaflet

To download and print this walk, please open / download the PDF version here

Open/Download
The view over the sand dunes of Merthyr mawr from Locality 1 these are as recent as the 16th century
The pink colured sandstone and conglomerate of Triassic age filling in the fissures in the Carboniferous aged limestone. The grey blocks within the pink are blocks of the older rocks that have been washed into the fissures along with the "younger" sands
Angular fragments of limestone in the Triassic Breccia showing the limited weathering that has taken place indicating a low movement from their source location
Obvious unconfirmity between the Carboniferous aged Limestone below and the Triassic aged conglomerate above
Caninia
The more rounded clasts and less pink coloured breccia at Locality 7 indicating more traansport weathering than at the previous locality.
The junction between the Carboniferous aged limestone and the Sutton Stone (above the red line) at Locality 8

•BGS Geology Viewer is a free smartphone app to view geological maps of Britain wherever you go https://www.bgs.ac.uk/technologies/apps/igeology-app/



We hope you enjoyed this short tour of Ogmore-by-Sea, Vale of Glamorgan. If you’d like to learn more about our local geology, take a look at other pages on the South Wales Geologists’ Association website: www.swga.org.uk

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This is some additional information and pictures to support the geology walk at Pontneddfechan. Take a look at the descriptions under each picture to see more information

The Localities mentioned on this post relate to the map which is included in the leaflet PDF and is repeated here to make this page easier to read. For more information and descriptions of all the localities and the start point, parking etc. please see the leaflet

To download and print this walk, please open / download the PDF version here

Open / Download
The Quartzite Bed in the Bishopston Mudstone Formation at Locality 3
A block that has been drilled and as used as a sleeper to hold the railway tracks on an old small mining railway that once used the valley floor as a track The lenscap is to show the scale (its about 75mm across) putting an object in a picture to give scale is something that geologists do so that they can measure things later if needed

Fossil bivalve Carbonicola at Locality 4. These are small and not easy to spot as you can tell from the scale. They would break up if collected so you are much better to take a picture and leave them for other people to see when they visit
An entrance to old mine workings at Locality 7. IT IS NOT SAFE TO ENTER!
However if you look through with a torch or take a picture you can seen the wonderfully crafted brickwork that makes up this tunnel. This tunnel is too small for regular use by people and was probably a drainage tunnel
The top of the Twrch Sandstone Formation described at Locality 9
The fossil burrows described at Locality 12

A useful addition to your walk is the BGS Geology Viewer which is a free smartphone app to view geological maps of Britain wherever you go https://www.bgs.ac.uk/technologies/apps/igeology-app/

We hope you enjoyed this short tour at Pontneddfechan. If you’d like to learn more about our local geology, take a look at other pages on the South Wales Geologists’ Association website: www.swga.org.uk

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This is some additional information and pictures to support the geology walk at Southerndown, Dunraven Bay. Take a look at the descriptions under each picture to see more information

The Localities mentioned on this post relate to the map which is included in the leaflet PDF and is repeated here to make this page easier to read. For more information and descriptions of all the localities and the start point, parking etc. please see the leaflet

To download and print this walk, please open / download the PDF version here

Open / Download
The thick bed of rock described at location 3 is clearly seen further west in the cliff
To the west of the car park. These cliffs look spectacular, but they are also dangerous and it's not a good idea to sunbathe at the foot of the cliffs. There have been fairly recent deaths by falling rocks on this coastline
Standing well back is also sensible on the eastern side and here looking at Location 4 with this wider angle view than the one in the leaflet, you can clearly see how the fault planes are not just in the lower corner, but are visible in the full height of the cliff
You can see that the rocks at the bottom are horizontal, whereas the ones above dip to the right of this picture. The Carboniferous rocks at the bottom of the cliff have been eroded and then at a much later time the jurassic rocks have been deposited on top of them. This time gap is called an unconformity. There is no way for geologists to know what happened in this location in that missing time record but by looking at other places where these rocks were not worn away they can infer a larger scale view of that missing time
A geologist standing well back and admiring the anticline (upwards fold) in the jurassic rocks at locality 9
Oysters (left) and Pinna (right) on the rocks of Southerndown beach foreshore
View of the Structures (folding and faulting) on the beach looking from Location 12 in the walk towards Nash Point

A useful addition to your walk is the BGS Geology Viewer which is a free smartphone app to view geological maps of Britain wherever you go https://www.bgs.ac.uk/technologies/apps/igeology-app/

We hope you enjoyed this short tour of Dunraven Bay. If you’d like to learn more about our local geology, take a look at other pages on the South Wales Geologists’ Association website: www.swga.org.uk

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This is some additional information and pictures to support the geology walk at Penwyllt and the ogof Ffynnon Ddu nature reserve. Take a look at the descriptions under each picture to see more information

The Localities mentioned on this post relate to the map which is included in the leaflet PDF and is repeated here to make this page easier to read. For more information and descriptions of all the localities and the start point, parking etc. please see the leaflet

To download and print this walk, please open / download the PDF version here

Open / Download
If you take the optional walk down the hill (and back), down through a wooden gate you can find the Ogof Ffynnon Ddu resurgence which is Locality 2. Resurgence is the term that describes the point at which an underground river reappears at the surface as as spring, the water here has flowed through the cave system and is cold even at the height of summer
South is to the right of this picture of the quarry face at Locality 3 The limestone dips in this direction.
Overview of the crags at Locality 4
The chert in the limestone at Locality 6
The wall of Penwyllt Bricks at the old Brickyard (Locality 7) should not be disturned or climbed on
At the old brick Kilns at Locality 7 you can find the glassy surfaces where the inside of the kilns melted

Below is a slideshow of pictures of the cave passages inside the "Top Entrance" of the cave seen at Locality 8

Click on the images to se elarger versions or manually drive the slideshow or just let it run

The view across the valley from Locality 10 to Fan Hir with the glacial morraines at the foot of the escarpment

A useful addition to your walk is the BGS Geology Viewer which is a free smartphone app to view geological maps of Britain wherever you go https://www.bgs.ac.uk/technologies/apps/igeology-app/

We hope you enjoyed this short tour of Penwyllt and Ogof Ffynnon Ddu. If you’d like to learn more about our local geology, take a look at other pages on the South Wales Geologists’ Association website: www.swga.org.uk