Edinburgh Castle in Scotland is built upon an ancient Volcanic Plug

A volcanic plug, also called a volcanic neck or lava neck, is a volcanic landform created when lava hardens within a vent on an active volcano. Edinburgh Castle is an ancient Stronghold which dominates the sky-line of the Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. Plate tectonics and hotspots Divergent plate boundaries At the Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures When forming, a plug can cause an extreme build-up of pressure if volatile-charged magma is trapped beneath it, and this can sometimes lead to an explosive eruption. Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface In Planetary science, volatiles, are that group of elements and compounds with low boiling points (see volatile) that are associated with a planet's or moon's Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet If a plug is preserved, erosion may remove the surrounding rock while the erosion-resistant plug remains, producing a distinctive landform. Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind

Volcanic plug in the Ochoco National Forest of Oregon, USA

Volcanic plug near Rhumsiki, Far North Province, Cameroon

Examples of landforms created in this way in the United States include Morro Rock, California; Lizard Head, Colorado; and Shiprock, New Mexico. The Ochoco National Forest is located in Central Oregon in the United States, north and east of the City of Prineville, location of the National Forest Oregon ( is a state in the Pacific Northwest region of the United States. Rhumsiki, also spelt Rumsiki and Roumsiki, is a Village in the Far North Province of Cameroon. The Far North Province, also known as the Extreme North Province (from French Province de l'Extrême-Nord) is the northernmost constituent province of The Republic of Cameroon is a unitary republic of central and western Africa. The United States of America —commonly referred to as the Morro Rock should not be confused with Moro Rock in Sequoia National Park. California ( is a US state on the West Coast of the United States, along the Pacific Ocean. Lizard Head (often called Lizard Head Peak) is a mountain in Colorado, one of the 637 peaks above 13000 feet in elevation in the state (see Thirteeners The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. Shiprock, ( Tsé Bit'a'í, "rock with wings" or "winged rock" is a rock formation rising nearly above the high-desert plain on the Navajo Nation New Mexico ( is a state located in the southwestern region of the United States of America. Devils Tower in Wyoming, as well as Little Devils Postpile located in Yosemite National Park, are also thought to be a volcanic plug by many geologists. Devils Tower ( Lakota: Mato Tipila, which means “Bear Tower” is a Monolithic igneous Intrusion or Volcanic The State of Wyoming ( is a sparsely populated state in the western region of the United States. Little Devils Postpile, in Yosemite National Park is a set of columnar joints in a basalt plug resembling the Devils Postpile formation A geologist is a contributor to the Science of Geology, studying the physical structure and processes of the Earth and planets of the solar system The only example of a volcanic plug in the eastern USA is the highly eroded Stark's Knob basaltic structure located along the Hudson River near Saratoga Springs, New York. Stark's Knob is a Basaltic pillow lava formation near Schuylerville New York, United States. The Hudson River, called Muh-he-kun-ne-tuk, the Great Mohegan by the Iroquois, or as the Lenape Native Americans called it in Unami Saratoga Springs is a City in Saratoga County, New York, USA. New York ( is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous However, some geologists believe Stark's Knob is not a plug at all, but merely an outcrop of an ancient submarine lava flow. The Ailsa Craig, Bass Rock and North Berwick Law are examples of volcanic plugs located in Scotland. Ailsa Craig ( Scottish Gaelic: Creag Ealasaid) is an Island in the outer Firth of Clyde, Scotland where granite was quarried to The Bass Rock, or simply The Bass, is an island in the outer part of the Firth of Forth in the east of Scotland, approximately one mile off North North Berwick Law is a conical hill which rises incongruously from the surrounding landscape (indeed this is the definition of the Lowland Scots word "law" Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. Borgarvirki is a volcanic plug located in north Iceland. Borgarvirki lies between Vesturhóp and Víðidalur in the north of Iceland, and at 177m above sea level it dominates the surrounding region

Subsequent glacial erosion can lead to exposure of the plug on one side, while a long slope of material remains on the lee side. "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. Such landforms are called crag and tail. A crag (sometimes spelled cragg, or in Scotland craig) is a rocky hill or mountain generally isolated from other high ground Examples include the Castle Rock in Edinburgh, Scotland. Edinburgh Castle is an ancient Stronghold which dominates the sky-line of the Edinburgh ( ˈɛdɪnb(ərə Dùn Èideann) is the Capital of Scotland and is its second largest city after Glasgow.