Xolobeni & the Continental Shelf
The Mzamba/Xolobeni area is located closer to the Continental Shelf than any other part of South Africa, and, interestingly enough, there is a cretaceous deposit and "petrified forest" at the mouth of the Mzamba river. Also interesting, although possibly unconnected, is the fact that the Pondoland Center of Endemism (PCE) seems to fall exactly adjacent to the "trench" where the Continental Shelf is closest to the actual African continent.
Amongst other weirdnesses this may play a role in the unique coastal flat rocks and reefs in the area.
The continental shelf regions contain the greatest amount of benthic life (plants and animals that live on the ocean floor).