Batholith

A batholith (from Ancient Greek (bathús), meaning "deep", and (líthos), meaning "stone") is a large mass of intrusiveigneous rock (also called plutonic rock), larger than 100 km (40 sq mi) in area, that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such as granite, quartz monzonite, or diorite (see also granite dome).