| A | B |
|---|
| metamorphic | Sedimentary rocks which have undergond great amounts of pressure and heat, and are transformed into a denser rock. |
| igneous | Rocks which are made when molten magma rises from beneath the earth and cools on the surface. This happens most with the eruption of a volcano. |
| sedimentary | Rocks which are made of smaller bits of rock. |
| erosion | The process by which large rocks are broken into smaller rocks, and eventually into grain or dust by wind and rain. |
| conglomerate | A sedimentary rock made of lots of different types of smaller pebbles. |
| sandstone | A sedimentary rock made of sand. |
| basalt | The most common igneous rock, made as a result of lava which cools more gradually |
| obsidian | Igneous rock made from lava which cools very rapidly. It is an extremely hard glass which was made to make early tools. |
| granite | An igenous rock which is not volcanic, and looks speckled. |
| limestone | A sedimentary rock made of lime, and commonly containing fossils, shells and small pebbles. |
| chalk | A type of limestone in which the fossils are too small to see with the naked eye. |
| marble | The metamorphic rock which results when limestone becomes extremely hot. |
| schist | Metamorphic rocks made of medium-grained material, and exposed to extremely high temerature. |
| flint | A sedimentary rock which was used to make Prehistoric tools. |
