Igneous intrusions are a type of rock feature ... It’s also an igneous intrusive feature, just like them. The rock they’re made of is called phonolite - also called a ‘sounding stone ...

An igneous rock has come ... the geographical distribution of the rocks, their connection with crust-movements, and the sequence of eruption of different types at a given centre.

There are three types of rock: igneous ... can occur either below the Earth’s surface, forming intrusive or plutonic igneous ...