| A | B |
|---|
| Catastrophism | The view that most of earth's geological features are the result of large-scale catastrophes such as floods, volcanic eruptions, et. |
| Uniformitarianism | The view that most of earth's geological features are the rsult of slow, gradual processes that have been at work for millions or even billions of years. |
| Humus | The decayed remains of once-living creatures. |
| Minerals | Inorganic crystalline substances found naturally in the earth. |
| Weathering | The process by which rocks are broken down by the forces of nature. |
| Erosion | The process by which sediments and rock fragments are carried away by wind or rain. |
| Unconformity | A surface of eroision that separates one layer of rock from another. |
| lamination | When a single layer of rock is less than 1 centimeter thick. |
| laminae | When several layers of rock are together, and each layer is less than 1 centimenter thick. |
| magma | When a volcano erupts, the lava that it sprews forth. |
| minerals | Inorganic crystalline substances found naturally in the earth. |
| metamorphic rock | Forms when heat or pressure or both are applied to any kind of rock. |
| igneous rock | Forms when lava or magma cools and crystals grow together, creating solid igneous rock. |
| sedimentary rock | Formed when any type of rock and plant and animal remains are weathered into sediments and then recombined to form rock by compaction, cementation, or precipitating out of solution. |
| stalactite | When the deposits start on the ceiling and form an icicle-like structure hanging down. |
| stalagmite | When the deposits form a structure that rises from the ground. |
