SUBSIDENCE IN PACIFIC CORAL REGIONS. 327 



where, evidence of comparatively recent eruption ; from it, 

 therefore, we gather no certain facts bearing on this subject. 

 , East of Tutuila is the coral island, Rose. It may be, there- 

 fore, that the greatest subsidence in the group was at its 

 eastern extremity. 



JFeejee Islands. — We have already remarked upon this 

 group (p. 158). A large amount of subsidence is indicated 

 by the extensive reefs in every portion of the group, but it was 

 greatest beyond doubt in the northeastern part. The sub- 

 sidence, where least, could hardly have been less than 2,000 

 to 3,000 feet. 



Ladrones. — The Ladrones appear to have undergone their 

 greatest subsidence at the northern extremity of the range, 

 the part nearest the centre of the coral area ; for although 

 the fires at the north have continued longest to burn, the 

 islands are the smallest of the group, the whole having dis- 

 appeared except the summits, which still eject cinders. The 

 southern islands of the group have wide reefs, which show 

 that they participated to some extent in the subsidence ; and 

 this is further indicated by the islands lying to the southwest, 

 in the line of the Ladrones. 



We have thus followed around the borders of the coral 

 area ; and, besides proving the reality of the limits, have as- 

 certained some fycts with reference to a gradual diminution 

 of the subsidence toward, and beyond, these limits. A line 

 through the Hawaian Group would pass along the northern 

 boundary line of the area ; and taking the southern boundary, 

 as given on page 319, the oblong area narrows eastward. 

 An axis nearly bisecting this space, drawn from the eastern 

 Paumotus toward Japan, passes through the region of greatest 

 subsidence, as above determined, and may be considered the 

 line of greatest depression for the great area of subsidence. 



