| A | B |
|---|
| bench mark | surveyor's marker usually placed permanently in the ground at a known position |
| ridge | narro area of high valleys between two valleys |
| glacier | large mass or body of moving ice |
| scale | describes the ratio between a measured distance on a map to the actual distance |
| intermittent stream | water flowing in it only during certain times of the years |
| valley | low area between higher land where rivers often flow |
| aerial photograph | photograph of the earth's surface taken from an airplan or spacecraft above earth |
| rapids | part of a river channel where water moves rapidly |
