IGNEOUS

Rocks have been ejected from the molten interior of the earth, and are either crystalline or fragmental. If they were ejected at the surface, and at the same time as the surrounding strata, they are called Volcanic or Contemporaneous c.g. lava, tuffs, etc. If they have only been laid bare, in the course of time, and are of later date than their surrounding strata, they are called Plutonic or Inti'usivc.