| A | B |
|---|
| aquifer | a layer of rock in which ground water can accumulate and flow freely |
| paleontologist | scientist who studies fossils in rock layers to learn about organisms, climates, and environments that existed in the past. |
| moraines | a ridge, formed when a glacier deposits its sediments |
| water table | the top of an aquifer |
| drainage basin | the land area from which a river system gets its water |
| flood plains | low-lying area on either side of a river or stream |
| V shaped valleys | steep cuts eroded into mountainsides by fast-moving water |
| Meanders | looping bends caused by rivers |
| oxbows | horseshoe-shaped lakes formed when the river takes a straighter course, cutting off a meander |
| fossils | the remains of once-living organisms |
| topsoil | soil located at the surface |
| subsoil | soil just under the topsoil |
| bedrock | Bottom (3rd) layer of soil. All soil begins as this |
| humus | organic matter made up of decaying material |
| tributaries | smaller streams that join together and make up a river system |
| index fossil | fossils that tell us the age of the rocks that they are in. |
| weathering | processes that break down rocks into smaller pieces |
| soil | made up of weathered rock, decaying plants, and decaying animals. |
| crust | top layer of the earth. Includes the continents and the ocean floor |
| sediments | rocks and soil that are carried by water |
