Mynydd Twyn-glas facts for kids

Quick facts for kids Mynydd Twyn-glas
Track leading up to Mynydd Twyn-glas from the south
Highest point
Elevation	472 m (1,549 ft)
Prominence	253 m (830 ft)
Listing	Marilyn
Naming
English translation	hill of the blue knoll
Language of name	Welsh
Geography
Location	Caerphilly, Torfaen, Wales
OS grid	ST 259978
Topo map	OS Landranger 171 / Explorer 152

Mynydd Twyn-glas is a mountain in South Wales. It stands 472 metres (about 1,550 feet) tall. This mountain stretches across parts of Caerphilly and Torfaen counties. It's located southwest of Pontypool and east of Newbridge. Mynydd Twyn-glas looks like a wide, flat area (a plateau) with steep sides. Many of these slopes are covered with tall pine trees.

A part of the mountain extending south is called Mynydd Maen. To the north, you'll find Mynydd Llwyd. The northern slopes are heavily forested and drop steeply into a valley called Cwm y Glyn.

What Mynydd Twyn-glas is Made Of

This mountain sits on the edge of the South Wales Coalfield. The top of the mountain and its upper slopes are made of a type of rock called sandstone. This sandstone belongs to the Pennant Sandstone Formation. It formed during the late Carboniferous Period, a very long time ago.

Coal and Rock Layers

Along the eastern sides of the mountain, you can find layers of coal. These layers are called the Cefn Glas and Brithdir seams. A large crack in the Earth's crust, known as the Glyn Fault, runs through the northwestern part of the mountain. Also, a big landslide has affected the southeastern slopes near Mynydd Henllys.

Exploring Mynydd Twyn-glas

Most of the open land on Mynydd Twyn-glas is open to the public. This means you can walk freely across it. This is thanks to a law called the Countryside and Rights of Way Act 2000.

Public Paths and Trails

Besides the open access land, there are also many public footpaths that cross the mountain. These paths make it easy to reach the mountain from nearby towns and villages.