The population of the great Polynesian archipelago presents many highly interesting and suggestive features, bearing closely on the question of oceanic migration. The area of Polynesia proper extends from the small islands westward of the Pelews to Easter Island, and from the Mariannes and the Sandwich Islands to New Zealand on the south. In Tongatabu and Easter Island, as well as in the Micronesian Rota, Tinian, Ualan, and throughout the Caroline group, remains of massive stone buildings, the origin or use of which is wholly unknown to the natives, reveal traces of an extinct civilisation, and afford some possible clew to the strange ethnological phenomena of the Oceanic archipelago. Professor Dana, who, as geologist to the United States Exploring Expedition, had abundant opportunities for observation, came to the conclusion that an immense area in the Pacific has for ages been gradually subsiding; and that the numerous Lagoon Islands mark the spots where what were once the highest peaks of mountains have finally been submerged. Mr. Hale, the philologist of the same expedition, gathered sufficient data from a European who had been resident for a time on the island of Bonabe, in the Caroline archipelago, and from his own observations, to satisfy him that the remarkable stone structures, both Ualan and Bonabe, were erected when the sites on which they stand were at a different level from what they now occupy. “At present they are actually in the water; what were once paths, are now passages for canoes, and when the walls are broken down the water enters the enclosure.”