| Question | Answer |
|---|---|
| Catastrophism | The view that most of earth's geological features are the result of large-scale catastrophes such as floods, volcanic eruptions, etc. |
| Uniformitarianism | The view that most of earth's geological features are the result 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. |
| Erosion | The process by which rock and soil are broken down and transported away. |
| Unconformity | A surface of erosion that separates one layer of rock from another. |
| Sedimentary rock | Formed from sediments (sand, silt, minerals, and other components of soil) that are laid down by water or some other agent. |
| Igneous rock | Forms from molten rock (magma) that cools and solidifies. |
| Metamorphic rock | When either sedimentary or igneous rock has undergone change due to extreme heat and pressure. |
| Lamination | When a single layer of rock is less than 1 centimeter. |
| Nonconformity | When stratified layers rest on top of unstratified layers. |
| Disconformities | When there are parallel, stratified rock Layers above and below the unconformity, but there is a clear surface of erosion between them. |
| Paraconformities | Unidentifiable unconformities. |
| Intrusion | "Veins" of igneous rock that shoot right through several layers of sedimentary rock. |
| Sills | Intrusions that run in the same direction as the strata. |
| Dikes | "Veins" that run perpendicular to the direction of the strata. |
| Weathering | The process by which rocks are broken down to form sediments. |
| Stalactite | Deposits that start on the ceiling and form an icicle-like structure hanging down. |
| Stalagmite | Deposits that form a structure that rises from the ground. |
| Column | The meeting of a stalagmite and stalactite to form a single structure. |
