| A | B |
|---|
| metamorphic | rocks that have changed into a more compact form by pressure, heat, and water |
| sedimentary | rocks made of loose earth materials cemented together by natural processes |
| igneous | rock made of molten earth material - the moving plates of the earth's crust are mostly made of this type of rock |
| coal (anthracite) | a metamorphic rock formed in swamps |
| peat | product of the first stage of coal formation |
| lignite | a soft brown coal that has lost most of its moisture |
| bituminous | coal that has lost all of its moisture |
| anthracite | the hardest coal and the cleanest burning; metamorphic rock |
| stalactite | deposit of calcium carbonate resembling an icicle |
| stalagmite | a deposit formed on the floor of a cavern by the dripping of water containing calcium carbonate |
| Paleozoic | the era known as "The Age of Fish" |
| basalt | dense rock found in the ocean floor, crust, and near some volcanoes |
| paleontologist | scientist who studies prehistoric life |
| salt | a mineral left behind when ocean water evaporates |
