Pen Allt-mawr facts for kids
Quick facts for kids Pen Allt-mawr |
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Pen Allt-mawr from Pen Cerrig-calch
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| Highest point | |
| Elevation | 719 m (2,359 ft) |
| Prominence | 102 m (335 ft) |
| Parent peak | Waun Fach |
| Listing | Hewitt, Nuttall, HuMP |
| Naming | |
| English translation | top of the big slope |
| Language of name | Welsh |
| Geography | |
| Location | Black Mountains, South Wales |
| OS grid | SO206243 |
| Topo map | OS Landranger 161 |
| Listed summits of Pen Allt-mawr | ||||
| Name | Grid ref | Height | Status | |
|---|---|---|---|---|
| Pen Twyn Glas | SN969193 | 646 metres (2,119 ft) | sub Hewitt, Nuttall | |
Pen Allt-mawr is a tall mountain peak in the Black Mountains of Wales. It stands at 719 meters (about 2,359 feet) high. It is the third highest peak in this mountain range. Pen Allt-mawr is a well-known and easy-to-spot mountain. It is part of a ridge that stretches south from a larger mountain called Waun Fach.
The mountain's name, Pen Allt-mawr, comes from the Welsh words meaning "top of the big slope." Its nearby peaks include Pen Twyn Glas to the north. To the south is its close neighbour, Pen Cerrig-calch. A noticeable part of the mountain, about 1 kilometer (0.6 miles) south-southwest of the top, is called Pen Gloch-y-pibwr. From this point, a ridge named Bryniog curves further south.
The very top of Pen Allt-mawr is rocky. You can find old stone piles there, called cairns. These cairns were built during the Bronze Age, a very long time ago. There is also a large stone shelter and a trig point. A trig point is a special marker used for surveying. More Bronze Age cairns are found along the western edge of the flat area to the south of the summit.
What is Pen Allt-mawr made of?
The very top of Pen Allt-mawr is covered by a type of rock called Quartz Conglomerate. This rock is part of the Old Red Sandstone group. These rocks formed during the Late Devonian Epoch. This was a time in Earth's history about 359 to 419 million years ago. The rocks on Pen Allt-mawr are connected to those found on Pen Cerrig-calch.
Below the Quartz Conglomerate are older sandstones. These are from the Brownstones Formation. They formed during the Early Devonian Epoch. These rocks make up the higher slopes of nearby mountains like Pen Twyn Glas. Some parts of this rock layer are softer. They wear away more easily. This is why the mountain has a stepped look. Even lower down the mountain, you will find sandstones from the Senni Formation. These rocks make up the lower slopes of Pen Allt-mawr.
