THE closing years of the nineteenth century witnessed a revival of interest in the petrology of gneous rocks, which must be regarded as marking an important stage in the development of that subject.

Sedimentary rocks are made up of pieces of older rocks (igneous, metamorphic, and sedimentary) and organic remains (shells, bone, etc.). When rocks break apart from erosion they are transported by ...

There are three types of rock found on Earth. These are igneous, metamorphic and sedimentary. Each rock type is formed in a different way. For example, the rock ...