| A | B |
|---|
| Fossils | The trace remains of an organism that lived long ago, most commonly perserved in sedimentary rocks. |
| Evolution | The gradual change in living things over a long period of time. |
| Uniformitarianism | A principle that states that geologic processes that occured in the past can be explained by current geologic process |
| Absolute Age (Dating) | Any method of measuring the age of an event or object in years |
| Law of Superposition | The principle that states younger rocks lie above older rocks if the layes have not been disturbed |
| Paleontologists | Scientist that study fossils/life |
| Fault | A break in a body of a rock.Along which one block slides relative/related to another |
| Extrusion | Lava that hardens at the surface |
| Original Horizontality | In horizontal sedimentary rock layers .The oldest layer is at the bottom. |
| Relative Age (Dating) | Any method of determining whether an event or object is older or younger than other events of an object |
| Index fossil | A fossil that is found in the rock layers of only one geologic age and that is used to establish the age of the rock layers.Also a print found in a sedimentary rock. |
| Extinction | The death of every member of speciesor the death of any animal kind |
| Geologic Time Scale | The standard method used to divide the Earth's long natural history into managable parts |
| Uncomformity | A break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time.Also called a break in the geologic record. |
| Intrusion | An instrusion is molten rock from Earth's interior that squeezes into existing rocks and cools |
