| A | B |
|---|
| index fossil | The fossil of an organism known to have existed for a relatively short period of time, used to date the rock in which it is found |
| fossil | preserved remains of an organism |
| groundwater | water that has sank into the ground and collected in pores |
| zone of saturation | a permeable layer that is filled with water |
| permeable | water can pass through |
| impermeable | water cannot pass through it |
| water table | upper surface of the ground water |
| acquifer | a layer of permeable rock that lets water flow freely |
| geyser | hot spring that erupts periodically |
| spring | place where the water table reaches the surface |
| carbonaceous film | preserves a plant or animal fossil in a thin carbon film |
| artesian well | pressure from a sloping aquifer causes water to flow |
| longshore current | water runs parallel to the shore |
| beaches | deposits of sediments that run parallel to the shore |
| barrier islands | sand deposits that parallel the shore |
| rill | a small channel forms on a slope |
| gulley | rill channel that becomes wider and deeper |
| drainage basin | land area from which a river gets its water |
| floodplain | large flat valley floor made by a meandering stream |
| alluvial fan | deposited sediments that are triangle shaped |
