Metamorphic rocks are made by either heating up or squashing the earth's crust. They are often found in mountainous regions. One example is slate. Slate was originally a black mud laid down on the bottom of the sea or lake. Fossils can sometimes be found in it but they are often squashed. Other common metamorphic rocks are called marble, gneiss, schist.
A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes. Examples of these rock types include marble, slate, gneiss, schist.
They can be formed by pressures deep inside the Earth, by tectonic processes such as continental collisions, or when they are heated up by an intrusion of hot molten rock called magma from the Earth's interior.
The coastline of Brazil is made up of metamorphic rocks. These are shown here as stripy lines.