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 tells the story of how Bilbo finds the One Ring of the Dark Lord. Originally, the ring meant nothing; it was just a magic ring. It was only after Tolkien's publishers asked him for a sequel that he gave significance to the ring and built an entire 1000+ page novel around it.