Garnedd-Wen Formation

Tarren y Gesail is a mountain in Snowdonia, north Wales. It is one of the Marilyns of the Cadair Idris group. Lying to the south of Cadair Idris, it and its neighbour Tarrenhendre form the bulk of the Tarren subgroup. The Tarrens rise from the south shore of the Llyn Mwyngil (Tal-y-llyn Lake) and end at the Dyfi estuary. The summit is a grassy ridge, which has a cairn and trig point. The views are extensive to the south and east, with Plynlimon and Cardigan Bay ahead, while the north views are dominated by Cadair Idris and Maesglase to the west. Between Tarren y Gesail and Tarren Hendre lies the Bryn Eglwys quarry, and Nant Gwernol railway station on the Talyllyn Railway, in the ravine of the Nant Gwernol stream. The Tarrerns can be thought of as forgotten mountains of Snowdonia, overshadowed by the popularity of Cadair Idris, occupying the sleepy south-western frontier of the national park.

Graig Goch is a 586m high hill in the Gwynedd area in Wales and lying within Snowdonia National Park. The hill falls within the communities of Llanfihangel-y-Pennant and Corris, the summit being located in the former. The hill takes the form of a NE-SW aligned ridge with a broad top which rise to subsidiary tops either side of the main summit. These are the 540m+ top of Mynydd Cedris (OS grid ref SH 707080) and the 504m top of Mynydd Rugog (OS grid ref SH 722092). The hill’s most notable feature is the large cliff which stretches the length of its northwestern face overlooking Tal-y-llyn, in part a major rock-slope failure.

Bryn Eglwys quarry was a slate quarry and mine near Abergynolwyn, in Merionethshire (now part of Gwynedd), Wales. More than 300 men worked at the site, making it the principal employer in the area. Two veins of slate, known as the Broad Vein and the Narrow Vein, were worked. The geology continues eastwards towards Corris and Dinas Mawddwy, and westwards towards Tywyn. It was one of many quarries that worked these veins. The site, which was in operation for just over 100 years, covered almost 2 sq mi (5 km2). It had several long tunnels up to 250 m (820 ft) to 350 m (1,150 ft). However, since closure all buildings have been demolished. Most of its inclines and infrastructure have become part of forestry plantations. From 1866 until closure in 1948, the quarry was served by the narrow gauge Talyllyn Railway, which took the slate down to Tywyn for transfer to the main line railway.

The Ceiswyn Formation (also known as the Ceiswyn Beds) is an Ordovician lithostratigraphic group (a sequence of rock strata) in Mid Wales. The rock of the formation is made up of interleaved beds of silty mudstones and siltstones with some sandstones and tuffs also present in small amounts. The formation runs diagonally across Mid Wales from close by Bala Lake to Cardigan Bay near Tywyn.

Tal-y-llyn, or Talyllyn, is a small hamlet and former parish in Gwynedd, Wales, situated at the end of Tal-y-llyn Lake close to the village of Abergynolwyn. The parish covered an area of 36,000 acres (15,000 ha). The River Dysynni flows out of the lake at this point, flowing down to enter Cardigan Bay north of Tywyn. Another lake known as Llyn y Tri Greyenyn or Llyn Bach was formerly located close to the border with the parish of Dolgellau. For much of the 19th century, and the first half of the 20th century, the predominant industry in the area was slate mining, in the quarries at Bryn Eglwys and Corris. The Talyllyn Railway was built in the 1860s to serve the quarries at Bryn Eglwys. Although this never reached the lake, and was never planned to do so, the terminus of the railway was in the parish, thereby giving the railway its name. Tourism is now one of the principle industries in the area, and the hamlet includes a hotel and public house. The parish church, St Mary's, dates from the 13th century, with the present structure dating from around 1590. It is a Grade II* listed building. John David Edwards, a cleric and hymn tune composer, is buried in the churchyard.

Tal-y-llyn Lake, (Welsh: Llyn Mwyngil), also known as Talyllyn Lake and Llyn Myngul, is a large glacial ribbon lake in Gwynedd, North Wales. It is formed by a post-glacial massive landslip damming up the lake within the glaciated valley. The hamlet of Talyllyn lies at the west end of the lake.

Tarrenhendre is a mountain in Snowdonia, North Wales. It is one of the Marilyns in the Cadair Idris group. Lying to the south of Cadair Idris, it and its neighbour Tarren y Gesail form the bulk of the Tarren subgroup. The Tarrens rise from the south shore of the Tal-y-llyn Lake and end at the Dyfi estuary. The summit is heathery and boggy, and has a small cairn to mark the highest point. The views are extensive to the south and east, with Plynlimon and Cardigan Bay ahead, while the north views are dominated by Cadair Idris and Maesglase to the west. Between Tarren Hendre and Tarren y Gesail lies the Bryn Eglwys quarry, and Nant Gwernol railway station on the Talyllyn Railway, in the ravine of the Nant Gwernol stream. The Tarrens can be thought of as forgotten mountains of Snowdonia, overshadowed by the popularity of Cadair Idris, occupying the sleepy south-western frontier of the Snowdonia national park.

Nant Gwernol railway station is the eastern terminus of the Talyllyn Railway near Abergynolwyn, Gwynedd in mid-Wales. It is 7 miles, 28 chains (11.83 km) from Tywyn Wharf. Nant Gwernol station was opened in 1976; before 1976 this upper part of the line had only been used for goods services.The station is built on the site of the former marshalling yard at the foot of the Alltwyllt incline, which was the first of the two inclines between the Talyllyn Railway and the Bryn Eglwys slate quarry. This site was chosen as the terminus of the passenger line, as it was the limit of locomotive working. The station building is of timber construction, based on the station building at Pendre and the original station building at Abergynolwyn. Trains only wait at the station long enough for the locomotive to run round, as there are no facilities at that point. Most trains pause at Abergynolwyn station to allow passengers time for refreshments. There is no road access to the station, though several footpaths lead off up the incline or towards the road between Bryn-Eglwys and Abergynolwyn. The station's name was taken from the nearby Nant Gwernol stream, and means "Alder Stream".

Abergynolwyn (English: Mouth of the River with a Whirlpool) is a village in southern Gwynedd, Wales, located at the confluence of the Nant Gwernol and the Afon Dysynni. The population of the community which is named after the village of Llanfihangel-y-Pennant was 339 at the 2011 census.

The Cwm Ebol quarry (also known as Cwmebol quarry) was a slate quarry about 1 mile (1.6 km) north west of the village of Pennal in Mid Wales. It operated from about 1860 to about 1906. It was the last Welsh slate quarry connected only to a trans-shipment point instead of directly to a railway.

The parish church of St Peter ad Vincula (meaning Saint Peter in Chains) in the village of Pennal in Gwynedd, north-west Wales, is notable as the site of the last senate meeting held by the Welsh prince, Owain Glyndŵr. It was founded in the 6th century, supposedly by St Tannwg and St Eithrias, and is the only church in Wales with this dedication. It is now part of the benefice of Bro Ystumanner in the diocese of Bangor.It is thought that the church was so named by Glyndŵr in competition with the chapel of St Peter ad Vincula in the Tower of London, one of the chapels royal of his rival, King Henry IV of England. Pennal was regarded with honour because of its status as one of the 21 llysoedd, the courts of the native Welsh Princes of Gwynedd.A copy of Glyndŵr's "Pennal Letter" of 1406, a letter to King Charles VI of France, setting out his plans for an independent Wales, originated from Pennal. While the original letter remains in the Archives Nationales in Paris, a copy is displayed at the Parliament House in Machynlleth, and at the National Library of Wales. The letter was briefly returned to Wales from France for an exhibition at the National Library of Wales in 2000, and a campaign has since sprung up for it to be returned permanently to Wales and put on show at the Senedd in Cardiff. A memorial garden was created in the churchyard for the native Welsh princes, during the rectorship of Rev Geraint ap Iorwerth, who was responsible for the church from 1989 until 2012. On his departure, he claimed that the church had become "cosy club for members who abide by the rules, accepting of their place in the hierarchy". He had previously been the centre of controversy when he burned pages from the King James Bible as part of an "art experiment". The garden contains a bronze statue of Owain Glyndŵr, made by Dave Haynes of Bethesda, which was unveiled in 2004. Local celebrity Robert Plant, who had made a donation towards the cost of the statue, attended the opening ceremony. Other notable donors included Ray Gravell, Aneurin Jones and Julia Ormond.The church is a Grade II listed building, much of which dates from the 18th century, the original medieval church having been rebuilt in 1700. The porch is built of stone from nearby Llugwy Quarry. The interior includes stained glass windows by Holland & Holt (1872) and by Ernest Penwarden (1923).

Mynydd Esgairweddan is a hill near Pennal in southern Gwynedd, Wales (grid reference SH6702). Nearby is the tiny settlement of Esgairweddan. It is very close to the site of the old Roman fort of Cefn Caer (Pennal). The area was described in the Topographical Dictionary of Wales by Samuel Lewis (published 1833) as; "A tract of hilly and rocky ground but little adapted for purposes of agriculture. The soil is thin and poor, but, in some of the lower grounds, not altogether unproductive; the declivities of the hills afford only a scanty pasturage for sheep and young cattle: peat, which forms the principal fuel of the inhabitants, is found in various parts."