Historical Features are physical or cultural features that are no longer visible on the landscape. Examples: a dried up lake, a destroyed building, a hill leveled by mining. The term makes no reference to the age, use, or any other aspect of the feature. A ghost town, for example, is not a historical feature if it is still visible.
Valley - Linear depression in the Earth's surface that generally slopes from one end to the other (barranca,
canyon, chasm, cirque, cove, coulee, draw, fjord, glen, gorge, gulch, gulf, gully, hollow, ravine).