Definition: Despite sounding like something out of Harry Potter, a batholith is a type of igneous rock that forms when magma rises into the earth's crust, but does not erupt onto the surface.

How do Laccoliths form?

A laccolith is a sheet-like intrusion that has been intruded within or between the layers of sedimentary rock, The laccolith forms when magma pushes through layers of rock above it and pools it in a dome shape. ... These structures are also known as plutonic formation or an igneous intrusion which are similar to the sills.

Where can batholiths be found?

Batholiths are vast, rising at least 100 square kilometers above the surface of the Earth, which is why they're so hard to miss. They are made up of plutons, which are themselves several kilometers in diameter. Batholiths can be found all over the planet, from Yosemite National Park to Canada's Coast Range.