Carreg Cadno facts for kids
Carreg Cadno is a cool hill in south Wales. Its name means 'rock of the fox' in English. This hill is about five miles northeast of Abercraf in the county of Powys.
Carreg Cadno is part of the amazing Brecon Beacons National Park and the Fforest Fawr Geopark. The top of the hill is 538 meters (about 1,763 feet) high. That's pretty tall! The hill is also inside the Ogof Ffynnon Ddu National Nature Reserve. This special area is looked after by the Countryside Council for Wales.
Contents
What is Carreg Cadno Made Of?
The rocks that make up Carreg Cadno are very old. They tell a story about Earth's past!
Southern Slopes: Sandstone
The southern part of the hill is made of a type of rock called Twrch Sandstone. This rock is a rough, sandy stone. It was formed a very long time ago, during the Carboniferous period. That was about 320 million years ago!
Northern Slopes: Limestone
The northern part of Carreg Cadno is made of Carboniferous Limestone. This limestone is found underneath the sandstone.
Cool Rock Features
The area around Carreg Cadno has some really interesting rock formations. These are typical of a karst landscape. This means the rocks have been shaped by water dissolving them over millions of years.
- Shakeholes: You can see hundreds of shakeholes here. These are like big dips or hollows in the ground. They form when water dissolves the rock underneath, and the ground above sinks down.
- Collapsed Caves: Sometimes, huge areas of rock have sunk because the limestone underneath dissolved. This caused giant underground caves to collapse.
- Rock Pavements: There are also areas that look like giant stone pavements. These are flat, exposed areas of limestone or sandstone.
Ice Age Clues
If you look closely at the gritstone pavements, you might see some scratches. These are called glacial striations. They were made by stones stuck in the bottom of a huge ice sheet. This ice sheet moved across the land during the last ice age, about 18,000 years ago! It's like the ice was scratching the rocks as it slid by.
Special Sand
You can also find pockets of silica sand here. This sand forms when the gritstone breaks down over time. This special sand was once very important! It was used to make refractory bricks. These are special bricks that can handle very high heat, like "firebricks." They were made at a factory nearby called Penwyllt Dinas Silica Brick Works.
Britain's Deepest Cave
One of the most exciting things about Carreg Cadno is what's underneath it! Ogof Ffynnon Ddu is Britain's deepest cave system. It lies right under the northern slopes of the hill.
Water from a stream called Byfre Fechan disappears into the ground at Pwll Byfre. This water then travels deep underground through the cave system. It reappears at a spring called Ffynnon Ddu. The difference in height between where the water goes in and where it comes out is 300 meters (about 1,000 feet)!
The National Nature Reserve was created to protect this amazing cave system. It also protects the plants and animals that live on the surface, which are supported by these unique rock features.
Visiting Carreg Cadno
Carreg Cadno is a great place for walkers and hikers! It's considered "open country," which means you can freely explore it.
A walking path called the Beacons Way crosses the northern side of the hill. This path goes from Ystradfellte to Penwyllt. Many people start their walk from a car park near the limestone quarry at Penwyllt. It's a fantastic way to see the beautiful Welsh landscape and explore this unique area.
