Broad Vein Mudstone Formation

The Abercwmeiddaw quarry was a slate quarry that operated between the 1840s and 1938. It was located at Corris Uchaf about 5 miles (8.0 km) north of Machynlleth, in Gwynedd, north-west Wales. The quarry was connected to the Corris Railway via the Upper Corris Tramway which carried its products to the Cambrian Railways at Machynlleth for distribution.

The Abercorris quarry (also known as Cwmodyn quarry) was a slate quarry worked between the mid-1840s and the early 1950s. It was located at Corris Uchaf about 5 miles north of Machynlleth, in Gwynedd, north-west Wales. The quarry was connected to the Corris Railway via the Upper Corris Tramway which carried its products to the Cambrian Railways at Machynlleth for distribution. It worked the Narrow Vein.

Corris Craft Centre is a craft and leisure complex in Corris, on the A487 near Machynlleth, mid-Wales. It is sometimes referred to as King Arthur's Labyrinth, one of the attractions on the site. Celebrating 40 years in 2022.

Braichgoch slate mine (often called Braich Goch quarry) was a large slate mine located in Corris Uchaf, north Wales. It was worked continuously from 1787 until closure in 1970 (some sources give 1971), apart from a hiatus in the 1900s. Most of the surface workings of the quarry were removed as part of a road widening and landscaping scheme in 1983. Part of the underground mine workings are now open to the public as the King Arthur's Labyrinth tourist attraction (a fantasy journey into Arthurian legend taking place on one level of the mine) and the newly launched Corris Mine Explorers. Through the subterranean Corris Mine Explorer expeditions, the working lives of 19th-century Welsh miners can be seen firsthand. Equipment and discarded personal belongings remain untouched as relics of Welsh industry. The landscaped site above ground is also home to the Corris Craft Centre, a retail site from which several craft based shops operate.

Corris is a village in the county of Gwynedd, Wales, about 4.5 miles (7 km) north of the town of Machynlleth. The village lies on the west bank of the Afon Dulas (which here forms the boundary with Powys), around that river's confluence with the Afon Deri. Its railway station is the headquarters and museum of the Corris Railway, a preserved narrow gauge railway. The area has a community council. The community council system replaced the former parish council system and tackles local issues, acts as a contact point between local government and residents for information and resources on various issues. The community elects one member to represent Corris/Mawddwy ward of Gwynedd Council. Besides Corris, the ward covers Mawddwy community to the north-east.

The Afon Deri (sometimes known as the Afon Corris) is a river in Mid Wales. It flows from the eastern flank of Mynydd Ty-Glas down to Corris, where it joins the Afon Dulas that flows south to the Afon Dyfi.The river passes through the village of Corris Uchaf and its lower reaches pass through the richest area of slate quarrying in Mid Wales. The Braichgoch, Abercorris and Abercwmeiddaw quarries are to be found beside the Afon Deri.

Corris Uchaf (English: Upper Corris) is a village lying in the south of the Snowdonia National Park in Gwynedd, Wales. The slate quarries that surround Corris Uchaf are its most prominent feature.

The Corris Railway (Welsh: Rheilffordd Corris) is a narrow gauge preserved railway based in Corris on the border between Merionethshire (now Gwynedd) and Montgomeryshire (now Powys) in Mid-Wales. The line opened in 1859 as a horse tramway, running originally from quays on the River Dyfi at Morben and Derwenlas, skirting the town of Machynlleth and then following the Dulas Valley north to Corris and on to Aberllefenni. Branches served the slate quarries at Corris Uchaf, Aberllefenni, the isolated quarries around Ratgoed and quarries along the length of the Dulas Valley. The railway closed in 1948, but a preservation society was formed in 1966, initially opening a museum; a short section of line between Corris and Maespoeth was re-opened to passengers in 2002. The railway now operates as a tourist attraction. A new steam locomotive was built for the railway, which was delivered in 2005. The two surviving locomotives, plus some of the original rolling stock, are preserved on the nearby Talyllyn Railway. The gauge of the railway is 2 ft 3 in (686 mm) which is unusual, and was shared by only three other public railways in the United Kingdom: the Talyllyn Railway, the short-lived Plynlimon and Hafan Tramway and the Campbeltown and Machrihanish Light Railway.

Garneddwen (also known as Garnedd-Wen; English: white cairn) is a hamlet in the south of the county of Gwynedd, Wales. It lies in the historic county of Merionethshire/Sir Feirionnydd, in the valley of the Afon Dulas. It consists primarily of a single row of terraced houses, built for the workers at Aberllefenni Slate Quarry. The hamlet was named after a large cairn ("carnedd" in Welsh) that was to be found in a field below the farm of the same name up to Victorian times.

Maespoeth Junction is a railway location to the south of Corris in Gwynedd. It lies in the historic county of Merionethshire/Sir Feirionnydd, in the valley of the Afon Dulas. It is known principally as a railway junction on the historic Corris Railway, and is also the site of a small number of residential dwellings.

Cambergi quarry (also known as Wenallt quarry) was a slate quarry in Cwm Hengae, west of Aberllefenni in North Wales. It operated between 1873 and about 1895.

The Narrow Vein Mudstone Formation (commonly known as the Narrow Vein) is an Ordovician lithostratigraphic group (a sequence of rock strata) in Mid Wales. The rock of the formation is silty, homogeneous or finely-laminated mudstone. It generally a medium blue colour. This formation has been commercially quarried as slate in several locations along its length. The formation is between 400 metres (1,300 ft) and 560 metres (1,840 ft) thick and runs from Dinas Mawddwy south-west to Cardigan Bay at Tywyn.