alkali flat alluvial plain basin billiard table bottomland bowling green bushveld campo champaign champaign country coastal plain dead flat dead level delta desert down downs earth esplanade fell flat flat country flats floor grass veld grassland ground heath homaloid horizontal horizontal axis horizontal fault horizontal line horizontal parallax horizontal plane horizontal projection lande ledge level level line level plane llano lowland lowlands lunar mare mare mean sea level mesa mesilla moor moorland open country pampa pampas parterre peneplain plain plains plane plateau platform playa prairie salt flat salt marsh salt pan savanna sea level sea of grass sebkha steppe table tableland terrace tree veld tundra upland vega veld water level weald wide-open spaces wold