<P> The continental margin is one of the three major zones of the ocean floor, the other two being deep - ocean basins and mid-ocean ridges . The continental margin is the shallow water area found in proximity to continent . The continental margin consists of three different features: the continental rise, the continental slope, and the continental shelf . Continental margins constitute about 28% of the oceanic area . </P> <P> The continental shelf is the portion of the continental margin that transitions from the shore out towards to ocean . They are believed to make up 7 percent of the sea floor . The width of continental shelves worldwide varies from a 30 meters to 1500 kilometers . It is generally flat, and ends at the shelf break, where there is a drastic increase in slope angle . The mean slope of continental shelves worldwide is 0 ° 07' degrees, and typically steeper closer to the coastline than it is near the shelf break . At the shelf break begins the continental slope, which can be one to five kilometers above the deep - ocean floor . The continental slope often exhibits features called submarine canyons . Submarine canyons often cut into the continental shelves deeply, with near vertical slopes, and continue to cut the morphology to the abyssal plain . The valleys are often V - shaped, and can sometime enlarge onto the continental shelf . At the base of the continental slope, there is a sudden decrease in slope, and the sea floor begins to level out towards the abyssal plain . This portion of the seafloor is called the continental rise, and marks the end of the continental margin . </P>

What is the true edge of the continental crust