The Cheviot () is an extinct volcano and the highest summit in the Cheviot Hills and in the county of Northumberland. Located in the extreme north of England, it is a walk from the Scottish border and, with a height of above sea-level, is located on the northernmost few miles of the Pennine Way, before the descent into Kirk Yetholm. The Cheviot was formed when melting in the crust over 390 million years ago gave rise to volcanic activity, and it has subsequently sustained intense erosion. Several watercourses radiate from The Cheviot. Etymology The name Cheviot, which was first documented in 1181 as Chiuiet, is probably of Brittonic origin. The name involves the element *ceμ-, meaning "a ridge", and the nominal suffix -ed, which in place-names can mean "having the quality of". Geography At above sea-level, The Cheviot is the highest point in the Cheviot Hills, the county top of Northumberland, England's highest point outside of Cumbria and fourth-highest outside the Lake District, after Cross Fell, Great Dun Fell and Little Dun Fell. It is located in the Northumberland National Park and is from the city of Newcastle-upon-Tyne. The summit is a triangular plateau covered with peat quagmires. Usway Burn, a tributary of the Coquet, rises on The Cheviot, as do College Burn, which merges with the Bowmont Water to form the River Glen near Kirk Newton, and Harthope Burn. Geology The Cheviot is an extinct stratovolcano eruptive during the Caledonian orogeny (490-390 Ma), in which volcanic activity arose from melting within the mantle crust. The mountain is heavily eroded, and originally may have been as high as , with a diameter perhaps of . Volcanic vents may have been located along the faults at Harthope and Thirl Moor. The earliest volcanic activity in the area was violent and explosive, with exposed ash and ignimbrite showing pyroclastic flows to have reached Coquetdale and Ingram. Later activity consisted of andesitic, trachyte and rhyolitic lava extrusion, which abnormally for such lavas, covered an area as large as . Lavas erupted from the Cheviot underlie Branxton and Flodden Ridge. Granitic magma was intruded into the layers of lava during the time period immediately before the volcano became inactive. The resulting pluton was exposed by erosion during the Carboniferous (+298 Ma). Glacial till in common in the area, which is a remnant of the Last Ice Age (< 115 Ka), during which the Cheviots