An intrusion is an igneous rock body that forms from crystallized magma under Earth's surface.any mountain ranges, such as the Sierra Nevada in California, are formed mostly by intrusive rock, large granite (or related rock) formations. Intrusions are one of the two ways igneous rock can form; the other is extrusive, that is, a volcanic eruption or similar event.
Admit it: you were pronouncing the word âSmaugâ â the name of the Hobbit dragon, the one whoâs in the subtitle of the upcoming movie installation â as âsmog.â.
The Hobbit is set in a time between the Dawn of FÃ¦rie and the Dominion of Men, and follows the quest of home-loving hobbit Bilbo Baggins to win a share of the treasure guarded by Smaug the dragon. Bilbo's journey takes him from light-hearted, rural surroundings into more sinister territory.