Editing Rhinogydd

{{Short description|Mountain range near Harlech, Wales}}
{{Use dmy dates|date=April 2022}}
The '''Rhinogydd''' (a [[Welsh language|Welsh]] plural form, often [[anglicised]] as '''Rhinogs''' and also known by the alternative Welsh plural '''Rhinogau'''{{fact|date=April 2025}}) are a range of [[mountain]]s located east of [[Harlech]] in [[North Wales]]. The name ''Rhinogydd'' derives from the names of two of the more famous peaks, [[Rhinog Fawr]] and [[Rhinog Fach]], although the greatest [[elevation]] in the range is reached by [[Y Llethr]], 756 m (2,480 feet).

[[Foel Penolau]], the northernmost summit of the range, was promoted to a Hewitt in 2018 following a new survey.<ref>{{cite web |title=Foel Penolau: How a Welsh hill became a mountain |url=https://www.bbc.co.uk/news/uk-wales-46441129 |website=BBC News |accessdate=9 December 2018}}</ref>

[[Image:Rhinog Fach and Y Llethr.JPG|thumb|300px|right|[[Rhinog Fach]] and [[Y Llethr]] from the slopes of [[Rhinog Fawr]]]]

The Rhinogydd are notably rocky and [[Calluna|heather]]-clad towards the northern end of the range, especially around [[Rhinog Fawr]], [[Rhinog Fach]] and towards [[Moel Ysgyfarnogod]]. The southern end, around [[Y Llethr]], [[Diffwys]] and the [[Afon Ysgethin|Ysgethin]] Valley has a softer, grassy character.

A population of [[feral goat]]s are in the range. Over 30 [[1 E7 m²|km²]] are protected as a [[Special Area of Conservation]] and a [[National Nature Reserve]].

==Geology==
The Rhinogydd are formed of hard [[sedimentary]] rocks of [[Cambrian]] age which occur as a major [[anticline|anticlinal structure]] known to geologists as the [[Harlech Dome]]. This structure which originated during the [[Caledonian Orogeny]] (mountain-building period) extends from [[Cadair Idris]] in the south to [[Blaenau Ffestiniog]] in the north. Its erosion by successive [[glaciation]]s has left the valleys and peaks of the Rhinogydd visible today.<ref>[http://www.eryri-npa.gov.uk/visiting/snowdonia-national-park/the-geology-of-snowdonia Snowdonia National Park - The geology of Snowdonia] {{webarchive|url=https://web.archive.org/web/20130916063812/http://www.eryri-npa.gov.uk/visiting/snowdonia-national-park/the-geology-of-snowdonia |date=2013-09-16 }} Retrieved 5 January 2012</ref> The core of the area is formed from the hard-wearing [[greywacke]]s of the Rhinog Formation. The formation also contains and is overlain by some [[siltstone]]s and [[mudstone]]s which form a broken zone of softer scenery around the periphery of the area's rugged core. In places, swarms of [[dolerite]] [[dike (geology)|dykes]] cut through the country rocks in a generally northwest–southeast direction. Much of the lower ground is mantled by [[glacial till]], a legacy of the last glaciation.<ref>British Geological Survey 1:50,000 scale geological map sheet 135/149 ''Harlech''</ref>

===History of geological investigations===
The geology of the area was first characterised by [[Adam Sedgwick]] and [[Roderick Murchison]] in 1835.<ref>Sedgwick, A. and Murchison, R.I. 'On the Silurian and Cambrian systems, exhibiting the order in which the older sedimentary strata succeed each other in England and Wales' Rep. Br. Assoc. Adv. Sci. (for 1835 Dublin), Trans., Sect., 59-61</ref> The [[British Geological Survey|Geological Survey]] began work in the area in 1846 and their first maps were published in 1855.<ref>Allen, P.M. and Jackson, A.A. "Geology of the Country Around Harlech" British Geological Survey 1985 {{ISBN|0-11-884367-2}}</ref> With the discovery of [[gold]] in the area in 1846 the state of geological knowledge increased dramatically. At least a dozen major publications appeared between 1844 and 1939.

==Hillwalking in the Rhinogydd==
{{unreferenced section|date=July 2022}}
The Rhinogydd are far less well known than the areas in the north of the [[Snowdonia National Park]], such as the [[Glyderau]], [[Carneddau]] and the [[Snowdon]] [[massif]] itself. This is due to the rugged nature of the landscape in the Rhinogydd and the fame of [[Snowdon]] as the highest peak in [[Wales]]. The Rhinog mountains are popular with [[hiking|hillwalkers]] looking for a more isolated, wilder walking experience.

The peaks of the range are most easily accessed from the west side. Two valleys - [[Cwm Nantcol]] ('valley of the Nantcol (stream)') and [[Cwm Bychan]] ('small valley') - lead deep into the mountains and may be reached from the village of [[Llanbedr]].

The most popular walking route in this area begins at the [[Roman Steps]] at 
{{coord|52|51|16.76|N|4|0|18.43|W|}}, which leads from Cwm Bychan through Bwlch Tyddiad and around [[Rhinog Fawr]]. Despite the name, these steps are not Roman and are in fact the well preserved remains of a [[medieval]] packhorse trail leading from [[Chester]] to [[Harlech Castle]]. At the top of the Roman Steps, the route curves around the eastern end of Rhinog Fawr and enters Cwm Nantcol via Bwlch Drws Ardudwy ('pass of the doorway of Ardudwy'). A different path leads from Cwm Nantcol, passing around the western end of Rhinog Fawr back to Cwm Bychan via Gloywlyn ('gleaming lake'), completing a circular route that can easily be completed in a day.

==Main peaks==
[[Image:Rhinogau panorama.jpg|thumb|600px|right|Panorama of the Rhinogau from the summit of [[Y Garn (Rhinogydd)|Y Garn]] with the [[River Mawddach]] estuary at far left and [[Diffwys]], [[Crib y Rhiw]], [[Y Llethr]], [[Rhinog Fach]] and [[Rhinog Fawr]] from left to right]]
The range contains the following [[Marilyn (hill)|Marilyns]]:
*[[Y Llethr]] 756 m
*[[Rhinog Fawr]] 720 m
*[[Rhinog Fach]] 712 m
*[[Y Garn (Rhinogydd)|Y Garn]] 629 m
*[[Moel Ysgyfarnogod]] 623 m
*[[Moelfre (hill)|Moelfre]] 589 m

the following [[List of Hewitt mountains in England, Wales and Ireland|Hewitts]]:
*[[Diffwys]] 750 m
*[[Foel Penolau]] 614 m

and the following [[List of Nuttall mountains in Wales|Nuttalls]]:
*[[Crib-y-rhiw]] 670 m
*[[Diffwys West Top]] 642 m

==References==
{{reflist}}


{{coord|52|48|49.64|N|3|59|18.34|W|display=title}}

[[Category:Dyffryn Ardudwy]]
[[Category:Ganllwyd]]
[[Category:Llanbedr]]
[[Category:Llanelltyd]]
[[Category:Llanfair, Gwynedd]]
[[Category:Talsarnau]]
[[Category:Trawsfynydd]]
[[Category:Mountains and hills of Gwynedd]]
[[Category:Mountains and hills of Snowdonia]]
[[Category:Sites of Special Scientific Interest in East Gwynedd]]
[[Category:National nature reserves in Wales]]