SUBSIDENCE IN PACIFIC CORAL REGIONS. 283 



about the heights of a single subsiding land of large size. 

 Such facts show additional error in the above estimate, evin- 

 cing that the scattered atolls and reefs tell but a small part of 

 the story. Why is it, also, that the Pacific Islands are confined 

 to the tropics, if not that beyond thirty degrees the zoophyte 

 could not plant its growing registers ? 



The island of Ponape, in the Caroline Archipelago, affords 

 evidence of a subsidence in progress, as Mr. Horatio Hale, the 

 Philologist of the Wilkes Expedition, gathered from a foreigner 

 who had been for a while a resident on this island. Mn Hale 

 remarks, after explaining the character of certain sacred struc- 

 tures of stone : " It seems evident that the constructions at 

 Ualan and Ponape are of the same kind, and were built for 

 the same purpose. It is also clear, that when the latter were 

 raised, the islet on which they stand was in a different condition 

 from what it now is. For at present they are actually in the water ; 

 what were once paths are now passages for canoes, and as 

 O'Connell [his informant] says, 'when the walls are broken 

 down, the water enters the inclosures.' '' Mr. Hale hence 

 infers "that the land, or the whole group of Ponape, and 

 perhaps all the neighbouring groups, have undergone a slight 

 depression." He also states respecting a small islet near 

 Ualan : '' From the description given of Leilei, a change of 

 level of one or two feet would render it uninhabitable, and 

 reduce it, in a short time, to the same state as the isle of ruins 

 at Ponape." 



In some of the northern Carolines, the Pescadores, and 

 perhaps some of the Marshall Islands, the proportion of dry 

 land is so very small compared with the great extent of the 

 atoll, that there is reason to suspect a slow sinking even at the 

 present time ; and it is a fact of special interest in connection 

 with it, that this region is near the axial line of greatest de- 

 pression, where, if in any part, the action should be longest 

 continued. 



Among the Kingsmills and Paum.otus, there is no reason 

 whatever for supposing that a general subsidence is still in 

 progress ; the changes indicated are of a contrary character. 



