The very finest sediment is kept in a state of movement until it drops into the gulleys or furrows of the shelf, where it can come to rest together with the finer fragments of the remains of littoral or bank vegetation.
The destruction of the grasses on the hillsides by overgrazing in recent years has increased the flooding by temporary streams, and consequently has tended to deepen and increase the gulleys and channels of the mountains and valleys.
The Islands The Islands are a number of shallow reefs and coral pinnacles with deeper sandy gulleys between them.