The Rhinogydd (a Welsh plural form, often

anglicised Anglicisation or anglicization is a form of cultural assimilation whereby something non-English becomes assimilated into or influenced by the culture of England. It can be sociocultural, in which a non-English place adopts the English language ...

as Rhinogs and also known by the alternative Welsh plural Rhinogau) are a range of

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

s located east of

Harlech Harlech () is a seaside resort and community (Wales), community in Gwynedd, North Wales, and formerly in the Historic counties of Wales, historic county of Merionethshire. It lies on Tremadog Bay in the Snowdonia National Park. Before 1966, it ...

North Wales North Wales ( ) is a Regions of Wales, region of Wales, encompassing its northernmost areas. It borders mid Wales to the south, England to the east, and the Irish Sea to the north and west. The area is highly mountainous and rural, with Snowdon ...

. The name ''Rhinogydd'' derives from the names of two of the more famous peaks, Rhinog Fawr and Rhinog Fach, although the greatest

elevation The elevation of a geographic location (geography), ''location'' is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational equipotenti ...

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. The Rhinogydd are notably rocky and 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 Ysgethin Valley has a softer, grassy character. A population of

feral goat The feral goat is the domestic goat (''Capra hircus'') when it has become established in the wild. Feral goats occur in many parts of the world. Species Feral goats consist of many breeds of domestic goats, all of which stem from the wild go ...

s are in the range. Over 30

km² The square kilometre (square kilometer in American spelling; symbol: km2) is a multiple of the square metre, the SI unit of area or surface area. In the SI unit of area (m2), 1 km2 is equal to 1M(m2). 1 km2 is equal to: * 1,000,000 squar ...

are protected as a

Special Area of Conservation A special area of conservation (SAC) is defined in the European Union's Habitats Directive (92/43/EEC), also known as the ''Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora''. They are to protect the 220 habitats and ap ...

and a National Nature Reserve.

Geology

The Rhinogydd are formed of hard

sedimentary Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedime ...

rocks of

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

age which occur as a major anticlinal structure known to geologists as the Harlech Dome. This structure which originated during the

Caledonian Orogeny The Caledonian orogeny was a mountain-building cycle recorded in the northern parts of the British Isles, the Scandinavian Caledonides, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events tha ...

(mountain-building period) extends from

Cadair Idris Cadair Idris or Cader Idris is a mountain in the Meirionnydd area of Gwynedd, Wales. It lies at the southern end of the Snowdonia National Park near the town of Dolgellau. The peak, which is one of the most popular in Wales for walkers and hikin ...

in the south to

Blaenau Ffestiniog Blaenau Ffestiniog () is a town in Gwynedd, Wales. Once a slate mining centre in historic Merionethshire, it now relies much on tourists, drawn for instance to the Ffestiniog Railway and Llechwedd Slate Caverns. It reached a population of 12,0 ...

in the north. Its erosion by successive

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...

s has left the valleys and peaks of the Rhinogydd visible today. The core of the area is formed from the hard-wearing

greywacke Greywacke or graywacke ( ) is a variety of sandstone generally characterized by its hardness (6–7 on Mohs scale), dark color, and Sorting (sediment), poorly sorted angular grains of quartz, feldspar, and small rock fragments or sand-size Lith ...

s of the Rhinog Formation. The formation also contains and is overlain by some

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

s and

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

s which form a broken zone of softer scenery around the periphery of the area's rugged core. In places, swarms of

dolerite Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grain ...

dykes cut through the country rocks in a generally northwest–southeast direction. Much of the lower ground is mantled by

glacial till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

, a legacy of the last glaciation.

History of geological investigations

The geology of the area was first characterised by

Adam Sedgwick Adam Sedgwick FRS (; 22 March 1785 – 27 January 1873) was a British geologist and Anglican priest, one of the founders of modern geology. He proposed the Cambrian and Devonian period of the geological timescale. Based on work which he did ...

and

Roderick Murchison Sir Roderick Impey Murchison, 1st Baronet (19 February 1792 – 22 October 1871) was a Scottish geologist who served as director-general of the British Geological Survey from 1855 until his death in 1871. He is noted for investigating and desc ...

in 1835. The Geological Survey began work in the area in 1846 and their first maps were published in 1855.Allen, P.M. and Jackson, A.A. "Geology of the Country Around Harlech" British Geological Survey 1985 With the discovery of

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

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

The Rhinogydd are far less well known than the areas in the north of the

Snowdonia National Park Snowdonia, or Eryri (), is a mountainous region and National parks of the United Kingdom, national park in North Wales. It contains all 15 mountains in Wales Welsh 3000s, over 3000 feet high, including the country's highest, Snowdon (), which i ...

, such as the

Glyderau The Glyderau (a Welsh plural form, also known in English as the Glyders) are a mountain group in Snowdonia, North Wales. The name derives from the highest peaks in the range, Glyder Fawr and Glyder Fach. According to Sir Ifor Williams, the w ...

Carneddau The (lit. 'the cairns'; is a Welsh language, Welsh plural form, and is sometimes anglicised to ''Carnedds'') are a group of mountains in Snowdonia, Wales. They include the largest contiguous areas of high ground (over or high) in England and W ...

and the

Snowdon Snowdon (), or (), is a mountain in Snowdonia in North Wales. It has an elevation of above sea level, which makes it both the highest mountain in Wales and the highest in the British Isles south of the Scottish Highlands. Snowdon i ...

massif A massif () is a principal mountain mass, such as a compact portion of a mountain range, containing one or more summits (e.g. France's Massif Central). In mountaineering literature, ''massif'' is frequently used to denote the main mass of an ...

itself. This is due to the rugged nature of the landscape in the Rhinogydd and the fame of

as the highest peak in

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

. The Rhinog mountains are popular with 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 Cwm or cŵm may refer to: * Cwm (landform), a rounded, glaciated valley, also known as a corrie or cirque * Combe, Cwm, a steep, narrow valley, or a small valley or large hollow on the side of a hill, also known as a combe * Cwm (software), a gene ...

('small valley') - lead deep into the mountains and may be reached from the village of

Llanbedr Llanbedr () is a village and Community (Wales), community south of Harlech. Administratively, it lies in the Ardudwy area, formerly Meirionnydd, of the county of Gwynedd, Wales. In 2011 the community had a population of 645. History Ancient ...

. The most popular walking route in this area begins at the Roman Steps at , 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 In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of World history (field), global history. It began with the fall of the West ...

packhorse trail leading from

Chester Chester is a cathedral city in Cheshire, England, on the River Dee, Wales, River Dee, close to the England–Wales border. With a built-up area population of 92,760 in 2021, it is the most populous settlement in the borough of Cheshire West an ...

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

The range contains the following Marilyns: * Y Llethr 756 m * Rhinog Fawr 720 m * Rhinog Fach 712 m * Y Garn 629 m * Moel Ysgyfarnogod 623 m * Moelfre 589 m the following Hewitts: * Diffwys 750 m * Foel Penolau 614 m and the following

Nuttalls Nuttall may refer to: People * Nuttall (name) * Nuttall baronets Nature * Nuttall's oak, a fast-growing large deciduous oak tree native to North America * Nuttall's woodpecker, a species of woodpecker found in oak woodlands of California * Nu ...

: * Crib-y-rhiw 670 m * Diffwys West Top 642 m

References

{{coord, 52, 48, 49.64, N, 3, 59, 18.34, W, display=title Dyffryn Ardudwy Ganllwyd Llanbedr Llanelltyd Llanfair, Gwynedd Talsarnau Trawsfynydd Mountains and hills of Gwynedd Mountains and hills of Snowdonia Sites of Special Scientific Interest in East Gwynedd National nature reserves in Wales