Craig y Llyn
Craig y Llyn (translates from Welsh as 'rock/cliff of the lake') is a mountain situated to the south of the village of Rhigos in the Cynon Valley on the south side of the upper Vale of Neath and north of the Rhondda Valleys in South Wales; it is the highest point in the traditional county of Glamorgan (Morgannwg), and the South Wales Valleys.
- For the subsidiary summit of Cadair Idris see Craig-y-llyn.
| Craig y Llyn | |
|---|---|
 The west face of Craig y Llyn | |
| Highest point | |
| Elevation | 600 m (2,000 ft) |
| Prominence | 392 m (1,286 ft) |
| Listing | Marilyn, council top |
| Coordinates | 51°42′57″N 3°35′06″W |
| Naming | |
| English translation | cliff of the lake |
| Language of name | Welsh |
| Pronunciation | Welsh: [ˈkɾaiɡəɬɪn] |
| Geography | |
  Craig y Llyn | |
| OS grid | SN906031 |
| Topo map | OS Landranger 170 |
Description
The summit of Craig y Llyn lies within the borough of Neath Port Talbot whilst its eastern slopes are within Rhondda Cynon Taf, the boundary running in a north - south direction 200 m (660 ft) to the east of the summit. The name derives from the sandstone cliffs which drop steeply down to the two lakes on its northern side. Ground on this side (but not the summit) has been designated as a Site of Special Scientific Interest.
The hill is covered by forestry, except for the steep north and northeast faces, and is crowned with a trig point. Several footpaths cross near the summit of the hill, including the Coed Morgannwg Way. The highest point in Neath Port Talbot, Craig y Llyn, is commonly known as the Rhigos Mountain after the village of Rhigos located on the northern side of the mountain in the Cynon Valley.
The Countryside Council for Wales states that the site has been categorised as a Site of Special Interest because it supports "...two special habitat features, and is also of special interest for a plant, the water lobelia. The first habitat feature is standing water, supporting aquatic plants typical of lakes with low nutrient content. Some of these plants are not known from anywhere further south in the UK. The second is dry heath, found on the slopes above the lakes.[1]
Geology
The hill is composed of a thick sequence of sandstones and mudstones assigned to the South Wales Coal Measures. The summit plateau is formed from the Pennant Sandstone of the Upper Coal Measures. The two cwms on its northern flanks which shelter Llyn Fach and Llyn Fawr are of glacial origin. In fact, the two lakes are the southernmost glacial tarns to occupy cwms in Great Britain. A landslipped mass of rock lies above the western end of the latter lake.[2]
See also
- List of Sites of Special Scientific Interest in Mid & South Glamorgan
References
- "Craig-y-Llyn". ccw.gov.uk. Archived from the original on 14 December 2014. Retrieved 30 October 2011.
- British Geological Survey 1:50,000 map sheet 231 'Merthyr Tydfil'