Fossils are the remainsrelics of living things, which were buried undergroundpetrified,then excavated by humansexposed by windrain. Fossils can be used to identify geological age, biological evolution, paleontological ecology, sedimentary environment,biological classification.They are essential materials for the study of geo-historypaleontology.Near Dongji Islet, there is a sea trough called “Penghu waterway”commonly known as "Heishuigou" due to its turbulent water flowdeep waterlarge waves.This waterway should have been formed during the last glacial period 27,000 to 18,000 years ago,when most of the seabed of the strait wasa land connected to the mainland.During thislong period of time, the mammals on the mainland may haveroamed on this raised land, where the ancient Min Riverthe ancient Jiulong River may have flowedflowed into the sea through the Penghu waterway. Animal remains near the riverbankmay have been swept into the Penghu waterway during a flood periodhave thus been preserved. The zoolites picked up in the Penghu waterway include Deshi buffalo, ancient rhomboid, ancient Ezo deer, ancient Japanese deerNama elephant teeth, among which buffalo skullslimb bones account for the vast majority. Shellfishfossil, foraminifera fossilsea urchin fossil are foundin the sedimentary rock layers on land. This fossil specimen was collected from the Penghu waterway.