SUBSIDENCE IN PACIFIC CORAL REGIONS. 331 



Mr. Hale remarks, after explaining the character of certain 

 sacred structures of stone : " It seems evident that the con- 

 structions 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 enclo- 

 sures. ' " Mr. Hale, hence infers " that the land, or the whole 

 group of Ponape, and perhaps all the neighboring groups, 

 have undergone a slight depression." He also states respect- 

 ing 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 Paumotus, there is no reason 

 whatever for supposing that a general subsidence is still in 

 progress ; the changes indicated are of a contrary character. 



I 



IV. PERIOD OF THE SUBSIDENCE. 



The period during which these changes were in progress, 

 extends back to the Tertiary era, and perhaps still farther back. 



