4. Landforms and Scale: Crustal Orders of Relief

To make a systematic study of the landforms, the geographers have divided the landscape into three orders of relief.

1. The first order of relief includes the continental platforms and the ocean basins. The continental platform is the land above the sea level and the ocean basins are the land below the sea level.

2. The second order of relief includes the mountains, plateaus and plains. In the ocean basins, it includes the continental shelves, continental slopes, abyssal plains, mid-oceanic ridges, submarine canyons and trenches.

3. The third order of relief includes the mountain peaks, cliffs, hills, spurs, sand dunes, valleys, gorges, caves, beaches, etc.