Cadair Idris or Cader Idris is a mountain in the
Meirionnydd
is a coastal and mountainous region of Wales. It has been a kingdom, a , a district and, as Merionethshire, a county. It is currently a committee area within the county Gwynedd.
Kingdom
(Meirion, with as a Welsh suffix of land, literally 'La ...
area of
Gwynedd
Gwynedd () is a county in the north-west of Wales. It borders Anglesey across the Menai Strait to the north, Conwy, Denbighshire, and Powys to the east, Ceredigion over the Dyfi estuary to the south, and the Irish Sea to the west. The ci ...
, Wales. It lies at the southern end 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 ...
near the town of
Dolgellau
Dolgellau (; ) is a town and Community (Wales), community in Gwynedd, north-west Wales, lying on the River Wnion, a tributary of the River Mawddach. It was the traditional county town of the Historic counties of Wales, historic county of Merion ...
. The peak, which is one of the most popular in Wales for walkers and
hikers, is composed largely of
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...
igneous rock
Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
The magma can be derived from partial ...
s, with classic
glacial erosion
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...
features such as
cwms,
moraine
A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a gla ...
s,
striated rocks, and
roches moutonnées.
Etymology
means 'Idris's Chair'.
Idris
Idris may refer to:
People
* Idris (name), a list of people and fictional characters with the given name or surname
* Idris (prophet), Islamic prophet in the Qur'an, traditionally identified with Enoch, an ancestor of Noah in the Bible
* Idris ...
is usually taken to be the name of a giant or, alternatively, it may refer to (or ), a 7th-century prince of
Meirionnydd
is a coastal and mountainous region of Wales. It has been a kingdom, a , a district and, as Merionethshire, a county. It is currently a committee area within the county Gwynedd.
Kingdom
(Meirion, with as a Welsh suffix of land, literally 'La ...
who won a battle against the Irish on the mountain.
was in fact referred to as ('Idris the Giant') in some mediaeval
genealogies
Genealogy () is the study of families, family history, and the tracing of their lineages. Genealogists use oral interviews, historical records, genetic analysis, and other records to obtain information about a family and to demonstrate kins ...
of Meirionydd.
The basic meaning of the word (
Middle Welsh
Middle Welsh (, ) is the label attached to the Welsh language of the 12th to 15th centuries, of which much more remains than for any earlier period. This form of Welsh developed directly from Old Welsh ().
Literature and history
Middle Welsh is ...
/
Early Modern Welsh or ) is 'seat, chair' (borrowed from the
Greek
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
, , 'chair'). In place names can mean 'stronghold, fort, fortress' or 'mountain or hill shaped like a chair'. The spelling represents a spoken variant of the standard form .
It appears that is the form used in the earliest Welsh-language sources. In a poem in his own hand in the second half of the 15th century, the poet wrote "" ('and then over Cadair Idris'). Around 1600,
John Jones of Gellilyfdy referred to "" ('the mountain, peak or hill known as Cadeir Idris').
The spoken form represented by had developed by the end of the Middle Ages and as a result the form was often used in English and
Latin
Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
documents at that time and in more recent documents in English and Welsh.
In his published in 1632,
John Davies of differentiated between the two words ('chair') and ('fort, fortress'), referring to and . That interpretation was followed by some later
lexicographer
Lexicography is the study of lexicons and the art of compiling dictionaries. It is divided into two separate academic disciplines:
* Practical lexicography is the art or craft of compiling, writing and editing dictionary, dictionaries.
* The ...
s, including
Thomas Charles
Thomas Charles (14 October 17555 October 1814) was a Wales, Welsh Calvinistic Methodist clergyman of considerable importance in the history of modern Wales.
Early life
Charles was born in the parish of Llanfihangel Abercywyn, near St Clears, Ca ...
and
Titus Lewis. It is now accepted, however, that is a spelling of a spoken form of , and that there is no evidence that and are separate words. But as it represents the pronunciation in the local dialect, the spelling is often seen in Welsh and English, and in June 2016
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 ...
decided to adopt that spelling on its signage, despite advice from the
Welsh Language Commissioner
The Welsh Language Commissioner () is a Welsh Government officer, overseeing an independent advisory body of the same name. The position was created following the passing of the ''Welsh Language (Wales) Measure 2011'', effective on 1 April 201 ...
and from Park officers, who favoured . The local dialect form is also seen in the name of the local secondary school,
Ysgol y Gader. The name of the mountain is typically spelt ' on current maps. The summit of the mountain is known as ('top of the chair/stronghold').
Ascent
There are three main trails that lead to the top of Cadair Idris. The summit, which is covered in
scree
Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits.
The term ''scree'' is ap ...
, is marked by a
trig point
A triangulation station, also known as a trigonometrical point, and sometimes informally as a trig, is a fixed surveying station, used in geodetic surveying and other surveying projects in its vicinity.
The station is usually set up by a map ...
. There is also a low-standing stone shelter with a roof.
Pony Path
The Pony Path (
Welsh: ''Llwybr Pilin Pwn''), which begins in the north from either
Dolgellau
Dolgellau (; ) is a town and Community (Wales), community in Gwynedd, north-west Wales, lying on the River Wnion, a tributary of the River Mawddach. It was the traditional county town of the Historic counties of Wales, historic county of Merion ...
or the
Mawddach estuary, is the easiest but the longest of the main trails. Its length from the mountain's base is with a climb.
Fox's Path
The Fox's Path (
Welsh: ''Llwybr Madyn''),This is the most direct way to the summit as the trail leads straight up the northern face. The ascent involves a climb up a
cliff
In geography and geology, a cliff or rock face is an area of Rock (geology), rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. ...
-
scree
Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits.
The term ''scree'' is ap ...
face. However, this part of the Fox's Path has been heavily eroded in recent years making the descent dangerous.
Minffordd Path
The Minffordd Path (
Welsh: ''Llwybr Minffordd'') starts on the southern side of the mountain near the
glacial
A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...
Tal-y-llyn Lake. Hikers using this ascent climb past Llyn Cau and along the rim of Craig Cau (rockwall) to Penygadair. Its length is and involves two climbs of over .
Geology
Cadair Idris is formed from a complexly fractured and
folded pile of both
sedimentary rock
Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...
s and
igneous rock
Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
The magma can be derived from partial ...
s of
Ordovician
The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...
age. They comprise the
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 and
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 of the Ceiswyn Formation which form much of the southern part of the mountain, together with the varied rocks of the underlying
Aran Volcanic Group. The steep cliffs rising above Llyn Cau to the north are formed from hard-wearing
basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
s and
tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...
s of the Pen y Gadair Volcanic Formation whilst those on the south side are acid tuffs of the Craig Cau Formation. The imposing cliffs which characterise the north side of the mountain are formed from a micro
granite
Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...
intruded into the Ty'r Gawen mudstones. In common with the rest of Snowdonia, the faulting and folding of this rock succession took place 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 ...
.
The crater-like shape of Cwm Cau has given rise to the occasional mistaken claim that Cadair Idris is an
extinct volcano
A volcano is commonly defined as a vent or fissure in the Crust (geology), crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface.
On Earth ...
(though as noted above, some of its bedrock is volcanic in origin). This theory was discounted as early as 1872, when
Charles Kingsley
Charles Kingsley (12 June 1819 – 23 January 1875) was a broad church priest of the Church of England, a university professor, social reformer, historian, novelist and poet. He is particularly associated with Christian socialism, the workin ...
commented in his book ''Town Geology'':
The natural bowl-shaped depression to which the name of ''chair'' has been attached, was formed by a
cirque glacier during multiple
ice age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...
s when snow and ice accumulated on these slopes partly through
avalanching. The glacier was up to a square kilometre in size surrounded on three sides by steep cliffs the highest being the headwall. The ''chair'' of Cadair Idris is this bowl-shaped hollow in the bedrock formed by the movement of glacial ice across the floor of the hollow,
abrading it and the lip over which it then flowed.
There are several tear-drop shaped knolls above the edge of Llyn Cau, each of which is a
roche moutonnée formed by the abrasive action of the moving ice. The two highest lakes are Llyn Cau and Llyn y Gader; the latter is thought to have a maximum depth of about .
Much of the area around Cadair Idris was designated a
National Nature Reserve in 1957, and is home to
Arctic–alpine plants such as
purple saxifrage and
dwarf willow.
Myths, legends and popular culture

There are numerous legends about Cadair Idris. Some nearby lakes are supposed to be bottomless, and anyone who sleeps on its slopes alone will supposedly awaken either a madman or a poet. This tradition (of sleeping on the summit of the mountain) apparently stems from bardic traditions, where bards would sleep on the mountain in hope of inspiration.
Although the mountain's name is typically taken to refer to the mythological giant
Idris
Idris may refer to:
People
* Idris (name), a list of people and fictional characters with the given name or surname
* Idris (prophet), Islamic prophet in the Qur'an, traditionally identified with Enoch, an ancestor of Noah in the Bible
* Idris ...
, who was said to have been skilled in poetry, astronomy and philosophy,
it has sometimes been mistranslated as ''Arthur's Seat'', in reference to
King Arthur
According to legends, King Arthur (; ; ; ) was a king of Great Britain, Britain. He is a folk hero and a central figure in the medieval literary tradition known as the Matter of Britain.
In Wales, Welsh sources, Arthur is portrayed as a le ...
(and to the
hill of the same name in Edinburgh),
an idea used by author
Susan Cooper in her book ''
The Grey King''. However, this translation is mistaken and there is no etymological or traditional connection between Idris and Arthur.
In Welsh mythology, Cadair Idris is also said to be one of the hunting grounds of
Gwyn ap Nudd
Gwyn ap Nudd (, sometimes found with the antiquated spelling Gwynn ap Nudd) is a Welsh mythological figure, the king of the '' Tylwyth Teg'' or " fair folk" and ruler of the Welsh Otherworld, Annwn, and whose name means “Gwyn, son of Nudd”. D ...
and his
Cŵn Annwn
In Welsh mythology and folklore, Cŵn Annwn (, "hounds of Annwn"), singular Ci Annwn (), were the spectral hounds of Annwn, the otherworld of Welsh myth. They were associated with a form of the Wild Hunt, presided over by either Arawn, king of ...
. The howling of these huge dogs foretold death to anyone who heard them, the pack sweeping up that person's
soul
The soul is the purported Mind–body dualism, immaterial aspect or essence of a Outline of life forms, living being. It is typically believed to be Immortality, immortal and to exist apart from the material world. The three main theories that ...
and herding it into
the underworld. Similarly the
Brenin Llwyd is also said to haunt a number of locations including Cadair Idris.
The mountain is mentioned several times and is used as a backdrop to the story of
Mary Jones and her Bible. This story is an account of a girl from
Llanfihangel-y-Pennant at the foot of the mountain who walked 25 miles to
Bala in order to buy a bible, which were scarce at the time. Jones' determined journey to get hold of a copy of the book in 1800 was a major factor behind the foundation of the
British and Foreign Bible Society
The British and Foreign Bible Society, often known in England and Wales as simply the Bible Society, is a non-denominational Christian Bible society with charity status whose purpose is to make the Bible available throughout the world.
The ...
in 1804.
"Tongues of fire on Idris flaring" is mentioned in the opening verse of the John Guard version of the song "
Men of Harlech".
In
Cassandra Clare's ''
Clockwork Princess'' Idris is where final battle between the protagonists and antagonist takes place.
References
External links
Information about Cadair Idris*Computer generated summit panorama
NorthSouth
A description of and guide to climbing Cadair Idris from h2g2
Cadair Idris Walk Via the Pony Path
Cadair Idris Long Walk from Llanfihangel-y-pennant
Summary of the Walks up Cader Idris
Walking on Cadair Idris - Inside Welsh Sport
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Arthog
Dolgellau
Abergynolwyn
Llanfihangel-y-Pennant
Mountains and hills of Gwynedd
Sites of Special Scientific Interest in East Gwynedd
Mountains and hills of Snowdonia
Hewitts of Wales
Landmarks in Wales
Marilyns of Wales
National nature reserves in Wales
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