Xiniu (Rhinoceros, for its shape) Islet has Dongju's best-known intertidal zone, the land area between high and low tides. Land emerges when the tide falls, giving rise to the land-linked island phenomenon. The islet is made up of sand, mud, and pebble beach, along with reef stone. Since it is located outside the mouth of the Min River in Fujian Province, the mingling of fresh and saltwater here nourishes an abundance of shellfish and other seafood: short-necked clams, purple sea urchins, stalked barnacles, horseshoe crabs, laver, silvermouth turban shells, and octopus, among other delicacies. When spring tides roll in, people come to harvest these seafoods in especially large numbers. The islet also home to the rare and precious Chinese wormwood, used in making medicinal wine that is good for rheumatism and other ailments. The islet's reefs are mostly composed of stone, making it good for fishing the rich stocks of heckle discus, blackedge nibblet, perch, and other fish.